Southampton 4-3 on penalties on Tuesday night.
Kepa Arrizabalaga started in goal for Edouard Mendy who was rested by Thomas Tuchel while Kai Havertz starts up front with Romelu Lukaku and Timo Werner still injured.
The hosts were left frustrated for a larger part of the first half until Havertz sent Stamford Bridge into a frenzy with the opener one minute to the break.
However, the lead did not last long thanks to Che Adams (47′) who beat Arrizabalaga just two minutes after the break to draw Ralph Hasenhüttl’s men level.
Hasenhüttl’s side stood their ground throughout the second half to force the game into penalty shootouts.
Adam began the shoot-out at Stamford Bridge begins and whips it into the top left before Marcos Alonso levelled up to make it Saints 1-1 Chelsea.
Arrizabalaga saved Theo Walcott’s penalty and made way for Mason Mount to hand Chelsea the advantage but a brilliant save by Forster kept it all square.
Shane Long and Callum Hudson-Odoi netted their penalties to make it 2-2 before Will Smallbone blasted his wide to hand Chelsea the advantage.
Ben Chilwell then scored to make it 3-2 but Oriol Romeu kept them in the game by beating Arrizabalaga to make it 3-3 with Chelsea left with the decider.
Reece James left nothing to chance and blasted the hosts into the next round as the shootout ended 4-3 in favour of the hosts.
