Arsenal coach Arsene Wenger was incredulous after being dismissed from the dug-out on Tuesday night - but he and his captain Kolo Toure had no complaints about the result as Sevilla ended the Gunners' long unbeaten record with a 3-1 victory.
Arsenal were handed a flying start to the Champions League clash at the Ramon Sanchez-Pizjuan when striker Eduardo da Silva gave them an 11th-minute lead.
At that point it looked like the already-qualified Gunners, who had not been beaten in a competitive match since April, would go on to secure the win that would guarantee them top spot in Group H.
But Seydou Keita became the first player to breach the Arsenal defence in six Champions League matches this season to draw Sevilla level in the 24th minute, before Luis Fabiano headed the hosts in front 10 minutes later.
Wenger was sent from the dug-out towards the end of the match after apparently becoming frustrated at what he felt was time-wasting by Sevilla captain Daniel Alves.
But the Gunners boss insisted afterwards he had no idea why he was handed his marching orders.
'The player was down, and when the guy [physio] came on the pitch he stood up - and two minutes later he was sprinting,' said Wenger.
'The referee came to see me, and I asked him why I was sent off. He said he would explain after the game. He could not give me any other reason.
'I'm not upset at all; I'm upset that we lost the game, that's all.'
Wenger, who stood by the advertising hoardings behind the dug-outs after his dismissal, was far from impressed by the performance of fourth official Reinold Wiedermeijer.
He said: 'The fourth official was very busy tonight throughout the game - that is the minimum you can say.
'I have played 100 games in the Champions League and I must say his behaviour was absolutely shocking. 'Where did he want me to go? I couldn't go in the stand.'
Arsenal had tried their best to get back into the game. But Sevilla continued to dominate, and former Tottenham striker Fredi Kanoute won and converted a late penalty.
Sevilla - making their Champions League debut this season - could have added more goals in a convincing second-half display, and Arsenal captain Toure said: 'They deserve their win. We gave everything, and that's the way football goes.
'The most important thing to do is to work hard and think about the next game.'
Wenger added: 'Sevilla deserved to win the game - and congratulations to them.'
In contrast to Arsenal's superb start to the season, Sevilla went into the match having lost their last two Primera Liga matches and seven in 12 overall this season.
At the weekend they were defeated 2-1 at home by Real Mallorca.
Kanoute, who netted against both Mallorca and Arsenal, said of on Tuesday night's win: 'We have shown the level of play that we always want to give.
'I hope that this will be the benchmark and that we continue in the same way in the league. Today has returned the real Sevilla.'
Sevilla will clinch first place in the standings if they beat Slavia Prague in their final group match, and Kanoute is keen to make that a reality.
'I don't know which opponents are possible, the important thing is to be first,' he said.
'Of the big teams, it is better to face them as late in the tournament as possible and I hope that we can continue making history in this competition.'