A Nicolas Jackson goal saw Chelsea beat Brighton in an intense game at Stamford Bridge to set up a Carabao Cup fourth-round tie with Championship side Blackburn Rovers.
These two sides have dealt with each other a lot in the past 12 months with 10 members of staff having moved to Chelsea for around £200m – and the match carried an extra edge.
Jackson’s winning strike came in the 50th minute after a fine move.
That goal was the first Chelsea had scored in four matches and gave them a much-needed boost as boss Mauricio Pochettino looks to get his project moving in the right direction.
Ian Maatsen played the ball to Cole Palmer – excellent on his first start – who put the ball through Jan Paul van Hecke’s legs for Jackson to sweep home into the bottom corner.
Solly March had the chance to get Brighton level late in the second half when he was left unmarked but his header was straight at former Seagulls keeper Robert Sanchez.
Arsenal will host Blackburn in the week commencing 30 October as they look to secure a place in the quarter-finals.
Chelsea’s line-up included three former Brighton players and every time they touched the ball early in the match they were jeered by their former supporters.
Kaoru Mitoma had the first big opportunity when he skipped past Marc Cucurella and had his cross blocked by Sanchez.
The Spanish keeper, who joined from Brighton for £25m in the summer, had a difficult evening with the ball at his feet during the match.
Sanchez kicked the ball directly out of play a number of times, much to the enjoyment of the Brighton fans.
One sloppy pass also went straight to Joao Pedro on the edge of his own penalty area, but the mistake wasn’t punished as the Brazilian striker chipped over the bar.
Jackson was denied a second goal by Brighton keeper Bart Verbruggen’s block and then saw a 71st-minute finish ruled out for offside.
March tested Sanchez before Joao Pedro volleyed over from inside the area as the visitors pushed for an equaliser that didn’t come.