Chelsea need extra-time goal from Marcos Alonso to see off battling Plymouth in FA Cup

Ryan Hardie missed a penalty with two minutes in extra-time remaining as Chelsea held on to edge Plymouth Argyle in the FA Cup fourth-round tie at Stamford Bridge.

Malang Sarr gave the ball away and then brought down the Plymouth substitute who got up to take a weak spot kick which Kepa Arrizabalaga saved diving to his left.

Earlier, Macauley Gillesphey gave the League One outfit a shock lead, flicking home Jordan Houghton's free0kick in the eighth minute.

Chelsea hit the woodwork on three occasions from Mateo Kovacic, twice, and Callum Hudson-Odoi before equalising four minutes before the break through Cesar Azpilicueta's clever backheel from Mason Mount's cross.

Plymouth were under siege for most of the second half but Michael Cooper was outstanding in the Pilgrims goal and the defenders in front of him ably supported.

However on the stroke of half-time of the added 30 minutes, Kai Havertz exchanged passes with Timo Werner before pulling back for Marcos Alonso to guide home.

This seemed to be the end of the matter but the Blues still needed Kepa to repel Hardie's penalty to stop the game going into a shoot-out.

But for a dreadful spot kick there was little Plymouth did wrong against a first-choice Chelsea side. Their organisation is a credit to their manager Steven Schumacher and the character of the side to still believe and force Chelsea back and into mistakes in the second half of extra-time was immense. Their goalkeeper looks too good to play in the third tier but the same could be said for their defenders who were heroic. There can be questions asked of Chelsea in not being able to put away lower opposition and the form of Romelu Lukaku remains a big worry, but it seems churlish to focus on such matters in the face of such an effort from the lower league opposition. At seventh in League One they are well in the hunt for promotion and if this performance doesn't give them confidence, nothing will.

Cup ties often get superstar performances from the underdogs' 'keeper and this was one of those occasions. He was a rock throughout the match, dealing with crosses under heavy pressure, coming out to block shots at goal and produced a wonderful tip over the bar to deny Mason Mount. Cooper has another year to run on his contract at Home Park but if the Pilgrims do not go up he will certainly attract attention from a tier-two side in the summer you would imagine.

Chelsea: Kepa 7; Azpilicueta 8, Christensen 6, Rudiger 6, Sarr 6; Jorginho 6; Kovacic 7; Mount 7, Ziyech 7, Hudson-Odoi 7; Lukaku 5. Subs: Alonso 7, Havertz 6, Werner 6, Saul 5.

Plymouth Argyle: Cooper 9*; Edwards 7, Wilson 7, Scarr 8, Gillesphey 7, Grant 7; Camara 7, Houghton 7, Mayor 6; Jephcott 6, Garrick 6. Subs: Ennis 6, Hardie 6, Randell 6, Broom 6, Law 6.

8' GOAL FOR PLYMOUTH! Wow....Plymouth fans are delirious. A fine delivery from a free-kick on the left flank and Gillesphey glances the ball home.

10' OFF THE BAR! Hudson-Odoi gets in the box on the left-hand side and pulls back to Kovacic who rockets his shot against the bar.

30' OFF THE BAR! For the second time the Blues go so close. Ziyech dinks a cross to the back post and Hudson-Odoi heads at goal but hits the same part of the bar Kovacic did earlier.

38' OFF THE POST! Is it Plymouth's day? Lukaku lays the ball off to Kovacic 20 yards from goal and his shot beats Cooper but comes back off the inside of the post.

41' GOAL FOR CHELSEA! It has been coming but it is unexpected that it comes from Azpilicueta and he does it with a cool backheel from Mount's low cross from the by-line.

58' GOAL FOR CHELSEA - RULED OUT! It was another backheel from Azpilicueta but he was offside when Lukaku met Mount's corner.

105+2' GOAL FOR CHELSEA! Nice exchange of passes between Havertz and Werner sees the former then pull back for Alonso who started the move and slotted home with his right foot.

117' PENALTY FOR PLYMOUTH! A horrendous error by Sarr sees Hardie race into the box and the defender brings him down on his way to clearing the ball.

118' PENALTY SAVED! Kepa saves Hardie's kick diving to his left. It was a fairly weak attempt but the Blues stopper did what he had to do.