KEPA ARRIZABALAGA’S PENALTY heroics helped Chelsea avoid a shoot-out as the Blues edged past Plymouth 2-1 in the FA Cup fourth-round but only after extra-time.

The Spain goalkeeper guessed correctly and then smothered Ryan Hardie’s last-gasp spot-kick, after the Plymouth striker had been felled by Malang Sarr.

Marcos Alonso thought he had settled the tie with a neat finish in extra-time, only for League One Argyle to battle back and force one more opening.

Kepa kept his cool to conjure a fine save however, on a day where Chelsea markedly missed Thomas Tuchel after the Blues head coach tested positive for Covid-19.

The German could now be forced to miss Chelsea’s Club World Cup campaign in Abu Dhabi next week due to isolation regulations.

The Blues remain hopeful Tuchel will be able to head out to the United Arab Emirates next week, but the Chelsea squad will jet out without him on Saturday night.

Macaulay Gillesphey headed Plymouth into an early lead, converting ex-Chelsea youth midfielder Jordan Houghton’s whipped free-kick.

Cesar Azpilicueta levelled via a fine backheel finish just before half-time, with Chelsea having hit the woodwork three times.

The Chelsea skipper will surely know his cute effort carried undertones of Gianfranco Zola’s masterful flicked goal in the 4-0 FA Cup win over Norwich in 2002.

A first goal for the Spaniard in a year could not open the floodgates however, and the Blues were left to toil through extra-time for their win.

Chelsea’s day started in the disarray of Tuchel’s positive Covid-19 test, leaving assistants Arno Michels and Zsolt Low to take charge against Argyle.

The Blues clearly missed Tuchel’s energy and urgency on the touchline, with a lack of such attributes seeping into the hosts’ play.

The Pilgrims sent their disciples into raptures right from the off, with Gillesphey nodding home from Houghton’s set-piece.

Inch by inch the Blues built back into the contest however, striking the woodwork three times before finally conjuring an equaliser.

Mateo Kovacic powered strikes against the bar and the post, with Callum Hudson-Odoi also nodding against the goal frame.

Finally Chelsea found their leveller however, with skipper Azpilicueta delivering at a crucial stage just before the break.

Jorginho threaded a neat ball to Mason Mount on the right wing, and Azpilicueta’s fine backheel converted the England midfielder’s cross.

Romelu Lukaku should have netted when Hakim Ziyech exchanged passes with Mount and fired across the face of goal, but the off-kilter Belgian could not reach the ball at full stretch.

Chelsea did have the ball in the net again shortly afterwards, with Azpilicueta turning home another backheel after a corner. But this time the defender was offside, and so the effort was quickly chalked off.

Kepa produced a smart save to thwart replacement striker Hardie who sneaked clear on goal, with the tie still level into the last 20 minutes.

Chelsea failed to find the clincher in regular time however, with replacement Timo Werner eyeing a chance when through on goal only to see James Wilson slide in and flick the ball to safety.

As the whistle blew to sound extra-time, Azpilicueta could only shake his head at the Blues being forced into 30 more minutes amid an already relentless schedule.

The first period of extra-time came and went without incident until the final minute, where Chelsea belatedly took the lead.

Kai Havertz traded passes with Werner before laying a neat cutback on a plate for Alonso, who strode onto the ball and swept into the net.

Chelsea expected to ride out an event-less second period, but Plymouth had other ideas.

Hardie intercepted Sarr’s pass and raced into the area, only to be hauled down by the Frenchman.

The Plymouth forward stepped up to take the penalty, but was left to bury his head in his hands as Kepa produced a fine save, smothering the ball and protecting the Blues’ lead.