A SUPERB CONVERSION from wide on the left by Fin Smith, the second such place-kick from the Northampton out-half, means Leinster’s lead has been reduced to three points.

Ross Byrne restarts with his team 20-17 ahead and 75:23 on the clock.

There’s no decision for Leinster to make with Byrne’s restart – it has to go long into the Northampton 22.

Rónan Kelleher chases to make a low tackle on Juarno Augustus, with Jason Jenkins assisting up high.

Leinster’s long restart means Northampton opt to use their kicking game to get out of their own 22.

There’s still time for them to chase upfield and look for a penalty or turnover, so they decide against trying to run out from deep in their territory.

It’s Leinster fullback Ciarán Frawley who fields the kick from Saints scrum-half Tom James. There are still more than four minutes left as Frawley gathers so it’s immediately likely that Leinster will kick again.

Either way, they need a solid carry after receiving possession but instead they throw a sequence of passes that ends with the ball going to ground.

Frawley has some space to go forward himself after initially stepping off his right foot, with team-mates around him, but opts to pass infield to the retreating Jack Conan, who is a stronger ball-carrier into traffic.

Conan is caught by Smith and decides to offload to Joe McCarthy, who then looks to throw a short pass to Frawley just as he’s snaffled. McCarthy’s pass bounces to ground and Frawley has to turn to regather.

Frawley does opt to carry now and Leinster steady themselves. They go to their kicking game through scrum-half Jamison Gibson-Park, who hangs up a fine box kick.

The ball hangs in the air for just over four seconds and lands 20 metres upfield, allowing Robbie Henshaw to jump up and through the landing point.

Henshaw has always had good aerial skills and he wins this contest against James in commanding fashion to give Leinster a big boost.

They’re back in the Saints’ half with a chance to either conjure another try, win a penalty, or at least run the clock down further. 

They are likely to have reviewed this next passage, discussing what they might have done better. In the end, they’re turned over on 18th phase and leave themselves exposed to a counter-attack. Did they miss chances to break on the edge? Could they have kicked again to pile further pressure on Saints? 

We can see below that both Byrne and Jimmy O’Brien are signalling for the ball to be moved wider after Henshaw’s aerial win, but Byrne ducks back infield to carry in the end.

Northampton have organised themselves well, getting good linespeed close to the ruck to dissuade further passes, as well as width in the defensive line and backfield cover, so there’s no obvious glaring opportunity for Leinster.

Byrne carries and now the Irish province go to their narrow carrying game as Caelan Doris, Michael Ala’alatoa, Conan, and Jenkins carry directly off scrum-half Gibson-Park’s passes.

They go one wider on sixth phase as Henshaw steps up as first receiver and plays a short pass to Kelleher, then it’s back to playing off nine as Ryan Baird and Cian Healy.

On ninth phase, Leinster string together a four-pass sequence and Conan carries off Henshaw.

With Leinster having played further out towards the edge of the defence, there’s a glimmer of an opportunity on the next phase as O’Brien swings around the corner.

Gibson-Park skips Byrne to find O’Brien, who has James Lowe and Jamie Osborne outside.

We can see above that Osborne has some space in front of him, even if there is backfield cover out of shot.

Lowe is very flat to O’Brien, which cuts down the chance of O’Brien zipping a skip pass wider to Osborne. That kind of pass would bring the threat of an intercept from Northampton wing James Ramm too.

O’Brien could possibly loft a bridge pass up over the top but he’d have to put decent height on it to clear Lowe first of all, giving Ramm plenty of time to cover across onto Osborne.

So it’s easy to see why O’Brien carries himself, getting met by another fine Northampton tackle in a long series of them. Doris and Kelleher make strong carries to Leinster’s right, then there’s another decision to make out on an edge.

This time it’s Byrne who has to weigh up the risks involved in trying to find Baird close to the touchline. Northampton wing Tom Seabrook does a good job of closing up into Byrne’s eye line, dissuading him from firing a long pass out wide or hitting Osborne short.

With 77:30 on the clock now, Byrne carries again. 

Just after Byrne’s carry, Saints lock Alex Moon [5 below] takes a risk in trying to counter-ruck on Frawley from a side angle.

At the very next breakdown, Baird does something a little similar, coming from the side to clear assist tackler James just after he releases McCarthy.

But referee Mathieu Raynal doesn’t believe either action is worthy of a penalty. Perhaps he doesn’t see either of them or maybe he doesn’t believe they have a major material effect on the game.

Play continues and Leinster generate momentum in midfield as Kelleher carries strongly again before Osborne surges forward.

But the Leinster centre is chopped down by an excellent Angus Scott-Young tackle and then Smith cleverly dummies a jackal effort – what referees call a ‘matador’ – and that lures Ala’alatoa into coming off his feet beyond the ball. 

Because of the dummy action by Smith, it’s not seen as a penalty offence by Raynal but Ala’alatoa being out of the game suddenly leaves the ball exposed.

Henshaw is on the other side of the breakdown but now Courtney Lawes, who has already contested aggressively at several previous breakdowns, goes for the kill.

Henshaw redirects his attention to clear Lawes away but the Saints flanker has done enough to disrupt, with Gibson-Park losing track of the ball as he glances up to assess his options.

Because Osborne has kept his hands on the ball, it seems Raynal feels there’s no knock-on from Lawes here, so Scott-Young can come forward to hoover it up and launch a threatening counter-attack.

Leinster have to scramble in defence as slick Saints handling moves the ball to the right edge.

Byrne, O’Brien, and Lowe all try to stop the ball but get beaten by the Saints’ handling.

That means the scrambling defenders working back are key. Doris starts close to the turnover and works back towards the touchline.

Frawley also starts near the turnover and works back downfield, while the pacy Baird comes from the far side of the breakdown.

Saints are likely to reflect on whether they should have kicked from the edge here, given that the Leinster backfield is completely empty after the turnover.

Instead, they opt to hold onto the ball as George Furbank passes to Ramm just before he is taken out by Doris, who doesn’t seem to wrap his arms for a tackle on Furbank.

Doris could argue he’s simply sprinting to try to get across to Ramm but his actions do take another attacker out of the game for what’s to ensue.

Ramm slaloms back inside Baird and Frawley and it’s the backtracking O’Brien, having turned swiftly from his initial attempt to stop the ball, who dives to initiate the tackle on Ramm, with Frawley joining.

We can see that Lowe is also in the vicinity here, meaning Leinster’s entire back three – players often tasked with helping to cover the backfield – are concentrated into one area near the ball.

Fortunately for Leinster, Osborne has had the presence of mind to account for that.

Remember he was the one to carry before the turnover and he gets back to his feet to begin running in the opposite direction to where the ball initially moves.

As he moves, Osborne recognises that no one else is in the backfield so as the Saints recycle from the Ramm carry, Osborne keeps going rather than joining the frontline defence.

Osborne’s effort means that as Saints scrum-half James finds out-half Smith, all of the potential kick space that was beckoning only a second before.

Further infield, on the edge of the Leinster defensive line, Conan and McCarthy have made a big effort to get back onside before racing forward aggressively, to further narrow Smith’s options.

Northampton still sense their opportunity here but it’s clear how well Leinster have scrambled in the seconds after their turnover.

And Smith is still able to get the ball wide to the overlap as his pass finds hooker Sam Matavesi.

But again, Leinster handle the situation well.

Rather than racing forward to close Northampton down, watch how Osborne completely sits off, allowing Conan to turn back and work really hard to connect with his centre out wide.

It takes another big effort from Conan to cover across as Osborne buys him time and they prevent Saints from having a chance to score, with Conan making an excellent tackle on his inside shoulder after Matavesi passes to Augustus.

On the next phase, it’s impressive just how prepared Leinster are to come forward. This has become their calling card under Jacques Nienaber – the ability to generate linespeed even on phases after they have lost lots of ground.

The same is true on the next phase as Leinster get off the line and close up and in to prevent Saints from making another pass wide to the powerful Tommy Freeman, who is out of shot.

Gibson-Park and Frawley close strongly on the left edge of the defence, while Lowe is working across in the backfield, having already tracked back to the other side to cover in behind after Conan tackled Augustus.

Remarkably, Leinster are regaining momentum in defence even after being stretched on the counter. They keep coming forward on the next phase as Conan tackles again, then Kelleher and Healy cover the offload.

Leinster are obviously feeling the fatigue now but so too are the Northampton players, having already been forced to make more than 200 tackles in this game.

And it’s Leinster who pounce on the next phase as Emmanuel Iyogun’s carry leaves him isolated. He’s tackled by Henshaw and Doris combines with Conan to earn the jackal penalty.

It’s a fine tackle from Henshaw low on Iyogun to create the turnover chance and while Saints could argue that Doris never clearly releases with his left arm, the fact that both he and Conan get onto the ball and lift it is persuasive to referee Raynal. Penalty Leinster.

With 79:20 on the clock as Raynal pauses the game for Frawley to limp off, Leinster still have another play before the win is secured.

Byrne kicks down the left touchline and they have one more lineout to see it out.

It’s Baird calling the lineout at this stage, starting caller Ross Molony having been replaced by Jenkins. The key is avoiding Lawes, who is Northampton’s biggest defensive threat by some distance.

Leinster use a tempo lineout whereby they briskly walk in and go straight into their drill, with Conan stepping forward to jump at the front.

The Leinster pack snap into mauling shape and eke out a few metres upfield.

Rather than risking the ball getting swallowed up in the maul, Leinster decide to go infield for one final phase.

Henshaw carries with Harry Byrne – just on for Frawley – and Lowe in support but Northampton flood in on the counter-ruck searching for one last turnover. 

Byrne looks to latch onto Henshaw to help drive him into contact and ends up off his feet early as he looks to remove tackler Smith, meaning Lowe is hit by with the brunt of the three-man counter.

Kelleher is third Leinster player in and he does well not to flop straight down to ground and get penalised for sealing off. Still, the Saints drive him away to the right as they pile through.

Gibson-Park is trying to get his hands to the ball rather than driving in himself, so it’s left to Jenkins to rescue the situation. The Saints have veered off to Leinster’s right as they counter, making it look a little odd perhaps, but Jenkins clearly enters through the gate.

With Baird also arriving behind him and Gibson-Park committing to the mass of bodies, Leinster have managed to retain possession.

There is one final counter effort from Saints but Ross Byrne is able to pass the ball back to his brother, who has worked back in behind, and Leinster seal the win by finding touch.

After a frenetic final five minutes, Leinster’s place in the Champions Cup final is secure.