Arsenal striker Olivier Giroud must serve a three-match suspension after the Football Association rejected his claim of wrongful dismissal for a red card at Fulham.
The France international was dismissed by referee Andre Marriner in the final minute of Saturday's 1-0 win at Craven Cottage for jumping into a challenge with defender Stanislav Manolev.
Despite the Gunners' appeal, the FA this afternoon upheld the sending off, so Giroud will now miss three of the final four matches of the Barclays Premier League season - starting against Manchester United on Sunday.
A statement from the FA read: "Following a Regulatory Commission hearing today, Arsenal's Olivier Giroud has had his claim for wrongful dismissal rejected.
"Giroud was dismissed for serious foul play during his side's game against Fulham at Craven Cottage on Saturday 20 April 2013.
"The player's three-match suspension will therefore commence with immediate effect."
The loss of Giroud is certainly a blow to Arsene Wenger's squad as they look to lockdown Champions League qualification, the £13million summer signing from Montpellier having scored 17 goals.
Arsenal retain a slender one-point lead over fourth-placed Chelsea and are two ahead of north London rivals Tottenham, albeit having played a match more.
Gunners boss Wenger will now have to rethink his attacking options for crucial games against United, then at QPR and home to Wigan before Giroud will be eligible again on the final day at Newcastle.
Theo Walcott is one option for a central striker, and is currently leading scorer with 18, while German international Lukas Podolski is another who has been pressing for a start down the middle, looking to add to a tally of 14.
With Chelsea and Tottenham set to face each other at Stamford Bridge on May 8, Arsenal know if they maintain the momentum of five wins from their previous six league games, then a top-four finish will be within reach.
Arsenal have responded magnificently since they were beaten 2-1 at Tottenham on March 3, with their fine run of form kicked off by winning in Bayern Munich, albeit losing the Champions League tie on away goals.
Midfielder Alex Oxlade-Chamberlain feels were Arsenal to beat United on Sunday - when the Gunners are expected to form a guard of honour for the newly-crowned champions - then it would renew hope of a sustained title challenge next season.
Speaking in the London Evening Standard, the England midfielder said: "The win over Bayern wasn't enough to get us to qualify for the Champions League quarter-finals, but it was still a massive boost for us as a side.
"We are still feeding off the momentum of that and a win over United can have the same effect.
"Obviously it is a massive game for us with a Champions League place at stake, but it is also massive for next season with the confidence we can get from winning."
Oxlade-Chamberlain believes if everything comes together on Sunday, then there is no reason why Arsenal cannot inflict defeat on Sir Alex Ferguson's all-conquering squad.
"As a team we are as good as anyone in the Premier League, right up there with the best in Europe and worldwide," he said.
"There are a few things we need to tie up, but we have been working hard as a team and becoming an increasingly tight unit and we are winning games that we should win.
"We have quality players in our side and believe we can beat anyone."
"It (Champions League qualification) is going to be very difficult and intense, but we just have to ensure we are taking everything we can out of every game left.
"At the moment, it is going well - we just need it all to come together in one final push this season."
Arsenal expect to have midfielder Jack Wilshere available for Sunday's showdown, the England international having started on the bench at Fulham as he continues his recover from a recent lay-off with an ankle injury.