Roberto Martinez was not a popular man in Swansea even before last night, but the Wigan manager's standing among fans of his former club must surely have plummeted even further after he inspired his side to a 2-0 win in the Carling Cup fourth round.
Argentinian striker Mauro Boselli scored the opener in the 51st minute after being set up by Antolin Alcaraz's fine pass. And Ben Watson made sure of the win from the penalty spot in the last minute.
Swansea took nearly 5,000 fans to the DW Stadium and, as anticipated, they were soon in full voice, directing their ire and Judas chants at Martinez over his acrimonious departure from the club last year.
Both sides struggled to create chances early on but Swansea restricted the home side and looked the more dangerous in attack with Darren Pratley and former Latics midfielder David Cotterill lively.
Wigan took greater control of possession in the second half but still found it hard to find a way through a determined Swansea side. The chance they had been waiting for arrived in the 51st minute as Alcaraz split the visitors' defence with a superb through-ball. Boselli raced into the space and calmly rounded Yves Ma-Kalambay for his first goal since his £6m move to the club from Estudiantes in the summer.
Wigan applied the finishing touch in injury time after substitute Charles N'Zogbia was tripped in the area, and Watson struck from the spot.
Ipswich eased the pressure on manager Roy Keane after they came from a goal behind to book their place in the last eight and end Northampton's superb cup run.
The Cobblers – who dumped Liverpool out in the previous round – looked set for another shock when Liam Davis put them ahead early on at Portman Road. But goals from Carlos Edwards and Damien Delaney soon had the Championship side in front and Keane's men sealed their progress with Tamas Priskin adding a late third.
Birmingham needed penalties to see off Brentford at St Andrew's and had Kevin Phillips to thank for getting them to that point. The visitors looked set to progress after Sam Wood gave them the lead on 69 minutes. But Phillips scored in the last minute to force extra time, and when neither side could break the deadlock, it came down to penalties, which Birmingham won 4-3.