Alan Shearer and Micah Richards have criticised Malang Sarr's defensive display against Luton, which saw Chelsea have to come from behind twice to beat the Championship outfit in the FA Cup.

The reigning world and European champions were looking to book their place in the quarter-finals of the competition, but they got off to the worst possible start when Reece Burke put Luton ahead inside two minutes.

Sarr was deemed to have been at fault for the goal which saw Burke beat him in the air from a corner before Saul Niguez equalised on the 27th minute. But it was Sarr again who allowed Luton to retake the lead having mistimed his offside trap, allowing Harry Cornick to race through and score.

It was a night to forget for Sarr, who was handed a rare start by Thomas Tuchel, and Shearer believes the Frenchman was not aggressive enough in dealing with the Championship side. 

‘Sarr’s marking Reece Burke, meant to be… he’s too nice isn’t he, there’s not enough aggression there,’ Shearer said.

‘He’s a yard off him, he touches him, not enough. It’s a very good ball in and run and the contact is superb the way he guides it in that far corner.’

Richards added: ‘Like you say, once he’s got the run on him and he’s got the height on him as well… he’s not aggressive enough.

‘Sometimes if you’re a smaller guy you’ve just got to make sure you’re close to someone, stop him from being able to get that run.

‘It didn’t happen and he’s cost his team a goal.’

Sportsmail columnist Richards was also left bemused as to why Sarr would try and play an offside trap before Luton's second, insisting the centre back should've just stayed with his man.

‘I just don’t understand why you would risk there,’ Richards added.

‘His body shape is all wrong, you can see the striker’s leaning forward and going to make the run in behind.

‘Just stay with him. Why give yourself the opportunity to get behind on the run?’

Sarr has featured 16 times for Chelsea this season, making three appearances in the FA Cup and just four in the Premier League.

The Frenchman has only completed the full 90 minutes on 10 occasions this campaign given he's fighting for minutes with Antonio Rudiger, Thiago Silva, Andreas Christensen, Trevoh Chalobah and Cesar Azpilicueta, who also plays at wing-back. 

Chelsea are still competing on three fronts after booking their spot in the quarter-finals, as they look to add more silverware to the trophy cabinet, having already won the Club World Cup last month.