Arsenal's nightmare week went from bad to worse as they were knocked out of the FA Cup by Sunderland, while Norwich were upset in the fifth round by Leicester.
Bolton continued to enjoy the distraction of the competition after eliminating Millwall and David Moyes' Everton also progressed to the quarter-finals following a win over Blackpool.
However, Chelsea must meet Birmingham in a replay after troubled manager Andre Villas-Boas saw his team held to a draw in the lunchtime kick-off.
Arsenal's dreadful four days hit a new low as their last remaining realistic hope of ending their trophy drought this season disappeared in a 2-0 defeat at Sunderland.
Manager Arsene Wenger, whose future beyond the summer remains a subject of debate, had admitted the midweek humiliation against AC Milan in the first leg of their UEFA Champions League last-16 tie will haunt him for the rest of his life.
And the Frenchman will likely also always remember an FA Cup defeat by Martin O'Neill's superbly-rejuvenated Sunderland which almost certainly ensured the 2005 success in the same competition remains his club's last piece of silverware.
Long since out of the Carling Cup, 17 points off top spot in the Premier League and wishing for a second-leg miracle against Milan, Arsenal saw their misery increased by Kieran Richardson's deflected 40th minute strike and Alex Oxlade-Chamberlain's unfortunate 78th minute own-goal .
To compound the frustration of Wenger, who on Friday confirmed Per Mertesacker had undergone ankle surgery, Francis Coquelin, substitute Sebastien Squillaci and Aaron Ramsey all sustained injuries at the Stadium of Light.
Mid-table Championship side Leicester's trip to Premier League Norwich had been given some extra spice in the build-up to the match due to a row over the visitors' low ticket allocation at Carrow Road.
And a 2-1 upset will therefore be viewed as some form of justice by Nigel Pearson's team, with the Foxes also gaining some payback for the two defeats suffered at the hands of Paul Lambert's men in last season's Championship.
Sean St Ledger's opener had set the tone for a free-flowing tie, but Norwich were level before half-time when Wes Hoolahan equalised.
Norwich's captain for the day, in the absence of the rested Grant Holt, slotted home from the rebound after his initial penalty had been saved by Leicester goalkeeper Kasper Schmeichel.
But David Nugent was to score the winner in the 71st minute and mean Norwich's 20-year wait to reach the quarter-finals went on.
Bolton may be struggling in the Premier League but they remained FA Cup specialists after knocking out Millwall in a 2-0 win at The Den.
Arsenal loanee Ryo Miyaichi opened the scoring in the fourth minute when the teenager showed great composure to curl the ball into the far corner.
And striker David Ngog added a second just before the hour mark to ensure Bolton, who reached last season's semi-finals before being hammered by Stoke, again progressed to the quarter-finals.
It was welcome relief for boss Owen Coyle, who had been subjected to criticism since defeat by fellow relegation-fighters Wigan in their last league outing.
As is customary, Everton have come to life in the second half of the season and Moyes' side followed their recent Premier League wins over Manchester City and Chelsea with a 2-0 victory against Blackpool.
The game at Goodison Park, which was watched by former Everton striker Wayne Rooney, was as good as over before it began as the home side raced into a two-goal lead inside the opening six minutes courtesy of Royston Drenthe and Denis Stracqualursi.
Ian Holloway, who has promotion back to the Premier League as his priority this season, had named a much-changed Blackpool team and the decision did not work on Merseyside as the visitors' record of failing to reach the sixth round since 1959 continued, with Kevin Phillips missing a late penalty.
Andre Villas-Boas' future as Chelsea manager continued to look far from secure after a disappointing 1-1 draw with in-form Championship promotion hopefuls Birmingham in the lunchtime kick-off.
The performance showed last Sunday's summit meeting in which Villas-Boas' players reportedly challenged their boss did nothing to address the problems which led to their worst display of the season at Everton last weekend.
Chelsea had fallen behind after some appalling defending allowed David Murphy to give Chris Hughton's Birmingham a shock half-time lead at Stamford Bridge.
Colin Doyle also brilliantly saved a Juan Mata penalty and, although Daniel Sturridge eventually equalised, Chelsea simply did not do enough to avoid a replay on 6th March.
Fernando Torres, who has been under almost as much scrutiny as Villas-Boas, endured another wretched afternoon and was substituted at half-time, when Didier Drogba made his return from the Africa Cup of Nations.
And the tactical change epitomised the misfiring nature of Chelsea's performance and the reasons for doubt surrounding Villas-Boas, despite his post-match claims he continues to enjoy the 'unconditional' support of club owner Roman Abramovich.