Holders Chelsea survived a major FA Cup fourth-round scare as substitute Salomon Kalou denied Everton victory.
The Ivory Coast international struck 15 minutes from time to deny the home side a famous win and preserve the Blues' hopes of winning the trophy for the third time in as many years.
Louis Saha had given Everton a 62nd-minute lead, and there was late drama when Ramires hit the post at one end and Petr Cech pulled off a fine save to deny Jermaine Beckford at the other, but a replay will be required to split the sides.
Barclays Premier League counterparts Aston Villa, however, did ensure their place in the fifth round draw with a comfortable 3-1 victory over Blackburn despite having defender Nathan Baker sent off.
First-half goals from Ciaran Clark, Robert Pires and Nathan Delfouneso made substitute Niko Kalinic's 18th-minute equaliser irrelevant.
However, neighbours Birmingham did it the hard way after manager Alex McLeish made wholesale changes after their Carling Cup exertions in midweek.
The Premier League side trailed 2-0 to local rivals Coventry of the npower Championship with 26 minutes gone as Marlon King and Richard Wood got the visitors off to a dream start.
But, David Bentley launched a remarkable comeback 10 minutes before the break and after Stuart Parnaby's first goal in almost five years levelled things up, veteran Kevin Phillips snatched victory with a 73rd-minute winner.
Championship Swansea, however, were not so fortunate as they were dumped out of the competition by League One Orient.
The Londoners ensured their place in the hat for the fifth round draw with a 2-1 victory at the Liberty Stadium with Swans defender Alan Tate's 88th-minute own goal seeing them through after Cedric van der Gun had dragged the home side back into the game following Jimmy Smith's 35th-minute opener.
There was something of a shock at Vicarage Road too, where Watford of the Championship went down to Brighton of League One after keeper Rene Gilmartin made a mess of dealing with Ashley Barnes' 16th-minute shot.
League Two Stevenage, conquerors of Premier League Newcastle in the third round, were unable to extend their run further despite coming from behind at home to Reading.
Mikele Leigertwood put the visitors ahead with 23 minutes gone, but Darius Charles equalised with 18 minutes left, only for Shane Long to snatch victory for the Championship club at the death.
Burton's adventure also drew to a close at Burnley as a Chris Eagles double proved enough for the Clarets despite loan signing Calvin Zola's 80th-minute strike.
The all Premier League clash between Bolton and Wigan at the Reebok Stadium ended goalless, but there was plenty of action at Hillsborough.
League Two Hereford took a ninth-minute lead through Stuart Fleetwood, but Darren Potter's equaliser six minutes later set the scene for Clinton Morrison to score twice from the penalty spot, either side of Jermaine Johnson's 77th-minute strike as Sheffield Wednesday ran out 4-1 winners.Reuse content