Arsenal made hard work of dispatching Blackpool in the Carabao Cup but the Gunners progressed as both sides finished with 10 men at the Emirates Stadium.
The hosts, who will be at home to rivals Tottenham in the quarter-finals, appeared to be coasting after Stephan Lichtsteiner’s first goal for the club was added to by Emile Smith Rowe.
But Blackpool rallied and, after Matteo Guendouzi had been sent off for two fouls on Jordan Thompson, Paudie O’Connor reduced the arrears before also being dismissed as Arsenal secured a narrow 2-1 victory.
Unai Emery made nine changes but his side still featured the likes of Petr Cech, Henrikh Mkhitaryan and Aaron Ramsey – the latter starting despite his future having reportedly been resolved during a meeting with the club.
The Wales midfielder said in Lisbon last week that he had received no explanation as to why a contract offer had been withdrawn but he now looks set to walk away for nothing when his current deal expires in the summer.
Carl Jenkinson also came in for Arsenal, making his first appearance for the club in 701 days as he was joined in defence by debutant Julio Pleguezuelo.
As expected the hosts had plenty of possession at the start of the game but did not test their former goalkeeper Mark Howard in the opening half an hour.
That changed, however, when Lichtsteiner slid in to connect with Guendouzi’s fine, lofted pass into the box and put the Gunners ahead with their first shot on target.
Shkodran Mustafi then came close to adding a second but his close-range header was deflected behind before Guendouzi sent a low drive wide of the post.
The second goal came from a player some 16 years younger than Lichtsteiner, Smith Rowe turning home after Jenkinson’s cross had been knocked into his path by Howard.
Blackpool almost halved the deficit when O’Connor rose to meet a corner, heading against the frame of the goal with Cech nowhere to be seen as he burst from his line.
Guendouzi, who had fouled Thompson in the first half to earn himself a booking, was given his marching orders after 56 minutes for pulling back the same player.
Blackpool needed just 10 minutes after the red card to bring themselves back into the game, O’Connor again rising for a header, this time unmarked, as the Leeds loanee grabbed his second goal for the club.
Cech had appeared uncomfortable with Emery’s desire for his side to play out from the back, being caught out on numerous occasions during the early weeks of the season.
He returned here but was again left red-faced as he was challenged in the box by Blackpool captain Jay Spearing as Nathan Delfouneso turned into an empty net only to see the goal chalked out for offside.
Emery was suitably worried to introduce club record signing Pierre-Emerick Aubameyang from the bench for the last 15 minutes.
Top goalscorer for Arsenal so far this season, Aubameyang had little chance to add to his tally but was hacked down by O’Connor as the defender was sent off with six minutes remaining.