Unai Emery's side saw their 11-match winning run come to an end at Selhurst Park on Sunday, but they avoided falling short for a second game in a row, even if the performance left a lot to be desired.
An otherwise unremarkable first half was punctuated by Stephan Lichtsteiner's first goal for the club and 18-year-old Emile Smith Rowe seemingly wrapped things up in the 50th minute.
But Matteo Guendouzi's red card just before the hour for two cheap bookings boosted the visitors and they pulled one back through Paudie O'Connor soon afterwards.
They could not force the equaliser and their goalscorer was dismissed late on.
Arsenal eventually got a first shot on target in the 33rd minute and it provided them with the opening goal, as Lichtsteiner managed to nudge the ball into the bottom-left corner when stretching to reach Guendouzi's lofted pass.
They got themselves another early in the second half – Smith Rowe finding the net from close range after Mark Howard parried Carl Jenkinson's miscued cross to the midfielder.
Blackpool were offered encouragement soon after when Petr Cech knocked a corner delivery against his own crossbar.
Guendouzi was then shown a second yellow for a needless tug on Jordan Thompson and Blackpool capitalised 10 minutes later, O'Connor heading home from Thompson's corner.
Cech attempted to dribble his way out of danger 21 minutes from time and was tackled by Jay Spearing, but Nathan Delfouneso's goal was disallowed for offside.
Blackpool's hopes of getting a second ended with O'Connor being shown a straight red six minutes from the end for a cynical tackle on Pierre-Emerick Aubameyang.
What does it mean? Gunners show grit after making things hard for themselves
It was by no means an impressive collective performance from Arsenal and they shot themselves in the foot with Guendouzi's red card, yet after O'Connor's goal they generally - Cech's blunder aside - kept things tight.
Smith Rowe catches the eye again
After an impressive pre-season, Smith Rowe has continued to look the part for the Gunners. On Wednesday he was a driving force in midfield, always willing to run at the defence, and he got himself a goal.
Cech yourself before you wreck yourself
Playing for the first time since late September, Cech was back from injury and eager to impress after Bernd Leno's recent performances. Unfortunately, the veteran was poor. He looked susceptible to crosses and with the ball at his feet. The offside flag bailed him out after his worst moment.
Key Opta Facts
- Arsenal have reached the League Cup quarter-final for the third consecutive season - they’ve eliminated non-Premier League opponents in the fourth round in each of these seasons, beating Reading in 2016 and Norwich City in 2017.
- Matteo Guendouzi is the first Arsenal player to be sent off in the League Cup since Denilson against Blackburn Rovers in December 2007.
- Stephan Lichtsteiner became the oldest player to score a competitive goal for Arsenal since Sol Campbell scored aged 35 years 152 days against Porto in February 2010.
- Paudie O'Connor is the first player to both score and be sent off in the same League Cup match since Lewis Cook for Leeds United versus Doncaster Rovers in August 2015.
Arsenal return to Premier League action on Saturday and face their toughest task of the season so far as Liverpool visit. Blackpool host Bristol Rovers in League One.