Arsenal held off Blackpool for a 2-1 Carabao Cup win at the Emirates on Wednesday in a match that saw both team's finish with 10 players.
Arsenal went 2-0 up against Blackpool after Stephan Lichtsteiner stretched out a leg to convert into the far corner and Emile Smith-Rowe found the net when Carl Jenkinson's miscued cross came off the crossbar five minutes after the break.
Arsenal's Matteo Guendouzi was sent off for a second booking after 56 minutes and on-loan Leeds defender Paudie O'Connor headed home for Blackpool with 25 minutes to play.
The sending off for Guendouzi means he'll miss Saturday's Premier League home match against Liverpool.
O'Connor, however, was sent off with six minutes remaining for clattering substitute Pierre-Emerick Aubameyang and Arsenal held out to reach the last eight.