Arsenal managed to progress to the quarter-finals of the Carabao Cup after defeating Blackpool 2-1 at the Emirates Stadium.
The Gunners went into half-time with a one goal advantage after Stephan Lichtsteiner notched his first goal for the club.
Emile Smith Rowe doubled Arsenal's lead five minutes after the break, but Unai Emery's side were down to 10 men shortly after when Matteo Guendouzi was given his second yellow card.
Paudie O'Connor managed to pull one back for the League One outfit but, after they too received a red card, Blackpool couldn't find an equaliser and so it was Arsenal who progressed.
Arsenal's reward for scraping through is a mouthwatering north London derby against Tottenham at the Emirates Stadium.
Petr Cech was given his first start in goal since suffering an injury against Watford in October.
But, he didn't make the most of his opportunity.
Cech has struggled since making the move across London from Chelsea in 2015. He's made numerous mistakes in his three year spell.
And he made another disastrous error against Blackpool.
Emery's tactics require his players to play out from the back, something that Cech has struggled with.
And he showed once again on Wednesday night just how shaky he looks having the ball at his feet.
With 20 minutes remaining and Arsenal hanging on to a 2-1 lead, Cech had the ball in his own box and being closed down by an opposition player.
But instead of passing the ball out, or clearing it, Cech tried to be clever and deceive the Blackpool player.
He succeeded, but then got tackled by a different Blackpool player.
Nathan Delfouneso then put the ball in the empty net but, fortunately for Cech, the goal was ruled out for offside.
Watch the moment below:
That is poor. Arsenal fans were not impressed and many have lost any confidence they had in the Czech goalkeeper.
Emery was asked about the moment after the game and he came to the defence of his goalkeeper.
"We need to play with the goalkeeper," he argued, per football.london. "It's normal when the centre-back deals with the pressure from the opposition. We need to play with the goalkeeper and continuing building up our attacking moment.
"I want to give them confidence, give them calm and it's true after today with this mistake the supporters also, as the ball is arriving to him, it is better to continuing him and other players confidence to continue our style and our idea on the game.
"He has experience and also he can good and we are going to continue with this idea with security and confidence."