Arsenal sealed third place in the Premier League and a guaranteed spot in next season's Champions League as a pair of blunders by goalkeeper Marton Fulop sealed a 3-2 victory at West Bromwich Albion on Sunday.
A mistake from Fulop, only in the side because of an injury to Ben Foster, allowed Yossi Benayoun to hand the Gunners an early lead but the Baggies responded with goals from Shane Long and Graham Dorrans.
Andre Santos' strike shortly before half-time pulled Arsene Wenger's side level and Laurent Koscielny capitalised on another Fulop error to earn the most slender of victories in a pulsating final-day encounter.
The win ensured Arsenal held onto third, a place and a point above north London rivals Tottenham, who now face a tense wait to see if Chelsea win next weekend's Champions League final against Bayern Munich - which would rob Spurs of a spot in Europe's elite club competition.
It was a disappointing end to a superb 16-month spell with the Baggies for boss Roy Hodgson, who expressed his gratitude to fans in his programme notes as he now turns his attention to leading England into Euro 2012.
There was no place in the Albion line-up for Foster in what was the final game of his loan spell from Birmingham after the goalkeeper picked up a suspected groin injury in training on Saturday.
It meant a Baggies Premier League debut for understudy Fulop and his worst nightmares were realised within four minutes.
In an attempt to dispossess Robin van Persie, James Morrison stabbed the ball back towards his own goal, however Fulop's attempts to usher it into his area ended in disaster as he stumbled to leave Benayoun with the goal at his mercy.
Arsenal goalkeeper Wojciech Szczesny was more solid and did well to turn away a vicious low drive from Marc-Antoine Fortune which threatened to creep inside his near post away for a corner.
However, the Baggies only had to wait until the 12th minute for their leveller.
Morrison dissected the Gunners defence with a threaded through pass and Long, who appeared to be left onside by Carl Jenkinson, strode through to steer a precise shot low into the left corner.
Then, three minutes later the game was turned upside down, as the Baggies moved ahead.
Morrison was responsible for another fine assist as Dorrans headed his Scotland team-mate's clipped pass to his right to evade Jenkinson and Koscielny before planting a superb half-volley low beyond Szczesny.
Wenger struggled to hide his frustration on the touchline but the Gunners levelled on the half-hour mark.
Youssouf Mulumbu was dispossessed by Alex Song midway in the Baggies half and he fed Santos, who outfoxed Simon Cox before unleashing a stinging low shot which Fulop's outstretched hand was unable to prevent creeping inside his right post.
Theo Walcott was introduced in place of Tomas Rosicky upon the resumption and within 10 minutes the Gunners were ahead again courtesy of another calamitous error from Fulop.
Van Persie's corner looked routine enough for the Baggies goalkeeper, yet he somehow managed to punch the ball behind him to allow Koscielny to scramble home the Gunners' third - much to the frustration of his Albion team-mates.
Wenger will desperately hope this was not Van Persie's final appearance in a Gunners shirt, as although the skipper did not add another goal to his tally for the season he did make a telling contribution when he hooked a Jonas Olsson header off the line as West Brom sought another equaliser.