Arsenal are almost certain to end a seventh successive season without a major trophy after crashing out of the FA Cup in the fifth round 2-0 at Sunderland.
Kieran Richardson's slightly-deflected strike and Alex Oxlade-Chamberlain's own goal condemned Arsene Wenger's side to defeat, extinguishing the last realistic prospect the club had of ending a trophy drought that will now be extended over seven years.
While the north London club were undoubtedly poor throughout the match, they were not helped by suffering a fair share of misfortune - most notably the early injury suffered by Francis Coquelin that forced a defensive reshuffle (Sebastien Squillaci came on - the Frenchman was later substituted himself).
Sunderland had only really been forced to survive a dubious penalty shout (for a tackle on Robin van Persie by John O'Shea) by the time Richardson opened the scoring shortly before the break. It was a wonderful strike from the former Manchester United winger, who ran onto the ball after Sebastian Larsson's free-kick had been half-cleared to lash a left-footed effort that clipped a defender before nestling beyond Lukasz Fabianski's reach in the far corner.
That gave the home side going the lead going into the break, but it was predominantly through luck that the advantage was extended. Stephane Sessegnon bore down on goal with just 15 minutes remaining, before sliding the ball across to the supporting Larsson out on the right.
The Swede's shot from an acute angle came away off the post - but straight into the path of Oxlade-Chamberlain in the goalmouth, who was unable to get it out from under his feet as both he and the ball agonisingly crossed the goal-line.
It was perhap harsh on the young winger, who had made the effort to track back all of 70 yards after initially losing the ball in midfield.
From there Sunderland were relatively comfortable, with Sessegnon continuing to be a threat on the counter-attack as Van Persie and Mikel Arteta wasted the few openings their side created. In the end, the final whistle was almost a relief for the bereft losers, who will now have little choice but to regroup and refocus on finishing fourth in the Premier League.
Andre Villas-Boas was described in midweek as a dead man walking by former Chelsea boss Claudio Ranieri, but it was the name of another former fan favourite that rang around Stamford Bridge as chants of "Jose Mourinho" greeted the Blues' 1-1 FA Cup fifth round draw with Birmingham on Saturday.
Villas-Boas has been dealing with a mutiny from his players according to reports in several national newspapers, and for 62 minutes he appeared to be heading for the exit door at Stamford Bridge as Birmingham led through David Murphy's first-half strike. However, a Daniel Sturridge equaliser partially made up for an earlier missed penalty by Juan Mata, rescuing Chelsea and ensuring their name will be in the hat for the quarter-final draw.
Villas-Boas, who threatened his players with the axe if they did not begin to fight for the club, made four changes for the lunchtime kick-off with Gary Cahill, John Obi Mikel, Ramires and Ryan Bertrand all drafted in. Significantly, the misfiring Fernando Torres retained his starting spot despite the presence of Didier Drogba on the Chelsea bench.
With two of their most prolific goalscorers over the years, Drogba and Frank Lampard, missing from the starting XI Chelsea made a patient start, with goalmouth action at a premium in the first 20 minutes. Mata and Sturridge looked the most lively, and an ambitious piece of control by the Spaniard almost created the breakthrough - only for the ball to run out of play.
Birmingham, comfortable in defence, then went up the other end to silence the home crowd with the opening goal, which owed everything to shocking Chelsea defending. David Luiz, Ramires and Branislav Ivanovic all made poor attempts to clear a corner, and with several others standing motionless Murphy drifted in to smash home at the back post.
The goal was met with chants of "You're getting sacked in the morning", aimed at Villas-Boas, but Chelsea had the ideal opportunity to get straight back on level terms as Ramires immediately went up the other end to earn a penalty from Wade Elliot's trip. However, even Mata - one of Chelsea's brighter sparks this season - could not convert from 12 yards as Colin Doyle brilliantly turned the ball onto a post.
Birmingham's goal was only the fourth Chelsea had conceded in their last 12 FA Cup ties, and they were clearly rocked as Villas-Boas desperately searched for answers from the bench. Luiz fired in a 34th-minute free-kick that kept Doyle honest, while Sturridge sent a delicious dipping volley just over the bar, but Chelsea headed for half-time to the feint tune of "Jose Mourinho" being chanted from the stands.
Villas-Boas' answer was to replace Torres with Drogba at half-time, and the Ivory Coast international's histrionics instantly got the crowd going, with an equaliser to follow. For arguably the first time in the afternoon Ivanovic delivered a cross of quality on the hour, and Sturridge arrived unmarked to head home off the far post.
The goal was the youngster's seventh goal in six FA Cup starts for Chelsea, and it prompted a growing onslaught from the home side, who so nearly took the lead when Raul Meireles' effort was deflected over. However, with less than 10 minutes remaining Villas-Boas drew more criticism from the crowd, not for the introduction of Lampard but for the withdrawal of the lively Mata.
Those howls of disapproval nearly grew louder when Nathan Redmond was allowed to run clean through with three minutes remaining, but the Birmingham man was so desperate to use his right foot that he scuffed his effort straight at Petr Cech.
In the 3pm kick-offs 1995 FA Cup winners Everton made the most of a third consecutive home tie, comfortably beating Blackpool 2-0 at Goodison Park. The Toffees were ahead after just 47 seconds on Merseyside and will be considered an unwanted draw in the quarter-finals.
Former Real Madrid man Roysten Drenthe opened the scoring before Blackpool had any time to settle, sending a left-foot curler beyond Matthew Gilks after Marouane Fellaini's layoff. Drenthe then took the corner that led to Everton's second on six minutes, Denis Stracqualursi forcing home for a 2-0 lead that remained as Kevin Phillips missed a penalty at the death.
Norwich were the highest-profile casualties of the day as they slumped to a 2-1 defeat at home to Leicester. The Canaries have not progressed past the fifth round since 1992, and they let a fine chance slip through their grasp at Carrow Road.
Leicester signalled the threat of an upset when Sean St Ledger headed home at the near post from a corner after five minutes. However, the scores were level midway through the first half when Kasper Schmeichel fouled Elliott Bennett, allowing Wes Hoolahan to equalise at the second attempt after his penalty was parried back to him by Schmeichel.
The winning strike was a goal worthy of winning any game, though, with Kevin Nugent dancing through the Norwich defence after picking the ball up 40 yards out, rounding Jed Steer to nudge Leicester into the last eight.
The most-fancied fixture for an upset on Saturday came at The New Den, where Championship Millwall hosted Premier League relegation candidates Bolton. However, it took four minutes for Wanderers to begin making light of that prediction, eventually triumphing 2-0.
On-loan Arsenal man Ryo Miyaichi proved far more alert than any Millwall defender to hand Bolton their early breakthrough. The striker simply ran behind the back four as Millwall went to sleep, converting with ease to silence the hostile home support.
The defending for Bolton's second goal also left plenty to be desired, but David N'Gog still deserved much credit for holding off a strong challenge before slamming home with his left foot from 25 yards.