Manchester United v Chelsea

Momentum is a funny thing in football. Both hugely forceful but precariously fragile.

Take Manchester United in the last few weeks. There can be little doubt they’ve been the Premier League’s most on-form, formidable and dynamic side. The goals and points tallies say as much. Most impressively, though, their level of integration in midfield has been exquisite. They’ve cut apart a series of teams with the kind of quick attacking triangles that require constant honing.

Which is why it’s curious that Alex Ferguson made such radical changes to his line-up for the midweek trip to Benfica.

On the one hand, of course, it was perfectly understandable. The United manager has more than enough experience of European group stages to know that his squad would still be set up well enough to secure a point that probably won’t even be needed to top the table by the end. United just have a knack of getting through.

But the drop-off in performance was notable. The team wasn’t nearly as fluid or as dynamic.

And, although Ferguson was obviously resting many of his key men for today, the wonder is whether it will actually interrupt their integration. We’ve seen it happen on countless occasions in the past after all.

Chelsea, by contrast, haven’t been nearly as impressive as United. But their momentum has stayed on a constant upward curve – with the midweek victory over Bayer Leverkusen only emphasising that this is increasingly looking like a true Andre Villas-Boas team. Although they remained somewhat patchy, some of their moves were reminiscent of his emphatic FC Porto side. Not least David Luiz’s goal.

And, to a degree, momentum is going to be a more important factor than normal in one of these clashes. Because of the fact this is Villas-Boas’s first meeting with Ferguson, there’s no previous evidence to go on. No background on which to build.

As such, the game is likely to go one of two ways: either awfully cagey as both teams feel each other out. Or amazingly open as they both try and frighten each other.

Despite United’s recent dynamism, probably the former. Particularly if it’s the more ponderous Michael Carrick who replaces Tom Cleverley. On that point, however, Rio Ferdinand dropped a hint yesterday that it will be Darren Fletcher who starts for United. And his aggression could be important in blocking Juan Mata’s passes as the Spaniard cuts inside.

As is already becoming evident, stop Mata and you stop Chelsea.

Either way, it’s a game that’s going to tell us a lot about the current and future states of these teams.

Key issue: will United’s attackers look as awesome against a midfield as physically strong and compact as Chelsea’s?

Verdict: Manchester United 1-1 Chelsea

Tottenham v Liverpool

With two teams that are still very much in development, it is difficult to tell their exact quality from the early-season games.

Are Liverpool as fluid as their first three matches suggested? Or did the defeat to Stoke indicate that the “feel-good factor” following Kenny Dalglish’s appointment and his first full summer was still having an undue effect?

Have Spurs, by contrast, fallen as far away from the top four as the battering to Manchester City hinted? Or were they just missing a few key absentees and signings?

Certainly, Spurs looked a lot more like the Champions League-challenging side of the last few years against Wolves. And a team spine which includes Emmanuel Adebayor, Luka Modric, Sandro and Ledly King is certainly knocking on the door of football’s elite, at least. Amazing what a few signings can do. Their squad suddenly looks a lot more convincing.

You can, of course, say the same about Liverpool. But mostly when Luis Suarez is firing. Even more so than Spurs with Modric, Liverpool are already looking very dependent on their blue-chip attacker.

Dalglish will also be determined to prove that the Stoke defeat was an aberration borne out by bad refereeing decisions. A second defeat away from home, after all, would kill of a fair amount of their momentum.

Picking it up straight away is going to be important for both teams here. Particularly if, as now is looking increasingly likely, they’ll be competing in a very open race for fourth

Key issue: will Luis Suarez’s movement pierce a Tottenham midfield that looks short of protection?

Verdict: Tottenham Hotspur 1-1 Liverpool

Fulham v Manchester City

The opposition might have lessened for City. But the pressure has arguably increased.

Make no mistake, a seemingly routine game at Craven Cottage is a big chance for City to make a statement. For a start, they can go top of the league in their own right with United hosting a difficult game in Chelsea. Secondly, they can make that known to both of those sides before the Old Trafford match even kicks off. City start an hour before United and Chelsea and, if they go by previous form, they could be out of sight by the time that starts.

But the question is whether City can start to live up to that pressure now that it’s beginning to escalate. It would, of course, be ludicrous to suggest that we’re anywhere near the kind of tense games that characterise a title run-in. But this is the first time City have been in this situation. And it’s going to be interesting to see how they handle it. Particularly after they endured their first scare of the season, with that draw against Napoli.

If events went according to form and quality, of course, none of this colour would matter. City are an immeasurably superior side to a Fulham team who have toiled this season. Indeed it was a bad sign for Martin Jol that they couldn’t secure a win at home to Blackburn last week.

But Fulham still haven’t coughed up too many at the other end and they could well clog the supply lines for Edin Dzeko and Sergio Aguero.

City will just have to prove they can step up to the challenge. In more ways than one.

Key issue: can City pick up their attacking form after it – and particularly Samir Nasri – were so badly disrupted by Napoli in midweek?

Verdict: Fulham 0-3 Manchester City

Sunderland v Stoke City

You could forgive Sunderland for approaching this fixture with a strong degree of envy. Despite their greater outlay and stated ambitions, it’s Stoke that find themselves in the kind of position that the Black Cats crave: an upwardly mobile side who can unnerve the top teams and have genuine ambitions of the European places.

Sunderland, by contrast, seem in a constant state of flux. Bruce seems to change the team every transfer window. There’s no stability. And while that means they can occasionally be impressive – as with the 3-0 win over Chelsea last season – they can never quite escape the inconsistency of the mid-table.

With that in mind, they’re probably due some kind of response against Stoke given recent disappointments. But Stoke are likely to be as durable as ever. Could be a game where both cancel each other out. And, with Conor Wickham and Nicklas Bendtner starting for Sunderland, it’s likely to be a game where we see a lot of aerial action.

Key issue: can Sunderland’s aerial presence actually play Stoke’s defence at their own game?

Verdict: Sunderland 1-1 Stoke City

In video: Robbie Keane scores for LA Galaxy again