Aaron Mokoena headed the winner in the final minute of extra time as Portsmouth came from behind to beat Coventry 2-1 and reach the fourth round of the FA Cup on Tuesday.
Held 1-1 at home by second-tier Coventry, Portsmouth fell behind in the replay when Leon Best scored with a half-volley in the 22nd minute.
But Avram Grant's team, last in the Premier League and having major cashflow problems, forced extra time when Coventry defender Stephen Wright headed the ball into his own net when trying to clear the ball.
The match appeared set to go to penalties but Mokoena was left unmarked to head Portsmouth's winner in the last few seconds of extra time.
Portsmouth, which is banned from signing players during the transfer window because of cash problems which led to the players not getting paid on time, now has a lucrative home game against Sunderland for a place in the last 16.
Barry Ferguson fired Birmingham into the fourth round in a 1-0 victory over Nottingham Forest, ending Forest's 18-game unbeaten run.
The experienced midfielder netted his first goal for the club since joining Birmingham from Scottish champion Rangers in July. After a 0-0 draw at Forest, the only goal of the replay came in the 62nd minute at St. Andrews.
It was Birmingham's 14th league and cup game without defeat but Forest, which lies second in the second-tier League Championship, must now concentrate on getting promotion to the Premier League.
Birmingham visits Everton in the fourth round.
