Premiership: Fulham 2 - 1 Arsenal

Arsène Wenger said Arsenal's season had reached "the moment of truth" and the truth was brutally exposed last night, a deserved defeat confirming they are not good enough to win the title. The poverty of Arsenal's passing and defending proved as telling as Fulham's superior vibrancy and spirit, and Wenger made a mistake in underestimating his opponents and leaving out several players who would normally start.

This was Arsenal's third straight defeat on their Premiership travels and raises serious questions about whether they will get the point they need in Porto to guarantee progress in Europe. A bigger win would not have flattered Fulham, who had been tearing Arsenal apart long before Philippe Senderos's 63rd-minute red card capped one of Wenger's most miserable nights. This was one of the worst displays in a decade under him.

Privately, the manager is bound to regret omitting his first-choice full-backs, Emmanuel Eboué and Gaël Clichy, beginning with Cesc Fábregas on the bench and leaving out Freddie Ljungberg. He did so in the belief this team would beat Fulham and leave players refreshed for "tougher" tasks against Tottenham, Porto and Chelsea but Chris Coleman's team would not be patronised.

Fulham closed down relentlessly to hinder their opponents' flow, displayed a determination and cohesion that Arsenal did not match and exposed the weaknesses of opponents who could have been buried by the interval rather than 2-1 down. The distribution of Fábregas, a half-time substitute, was sorely missed by Arsenal and the inadequacies particularly of Alex Song and also the stand-in full-backs, Justin Hoyte and Matthieu Flamini, were unmistakable. Perhaps Wenger forgot Fulham beat Chelsea here last season.

To blame all on the manager's changes would be unfair. Jens Lehmann ought to have kept out the header with which Brian McBride gave Fulham an early lead, though he saved Arsenal on other occasions; Gilberto Silva lost too many tackles and gave away too much possession; Alex Hleb and Tomas Rosicky looked lightweight; Kolo Touré and Senderos error-prone, and the list goes on.

Rarely can Arsenal have created so few chances. Their goal came from a brilliantly struck Robin van Persie free-kick and Antti Niemi's only testing save came in the final 25 minutes when he pushed a Theo Walcott shot on to a post. Thierry Henry earlier thought he had equalised with a delicious finish but was ruled offside.

"The coincidence of the decisions against us at the moment is very peculiar," Wenger said, pointing also to a penalty not given at West Ham. Such hints at conspiracy miss the point, and it says much that Arsenal's defeat was not a great shock.

That is to take nothing from Coleman or his players, who defended soundly and attacked with verve. Luis Boa Morte was a constant threat against his former club with pace and movement, Michael Brown epitomised the workrate, Claus Jensen displayed a craft too many Arsenal players lacked and Moritz Volz impressed against his previous employers.

Apart from a period at the start of the second half Fulham largely held sway. It was bemusing that Wenger said his team "created chances and I'm not disappointed with the way we played", and felt hard done-by. "I will leave the mathematics of the title to you," he said. "We will go away and focus on the next game. It was our third away defeat in a row, we cannot deny that, but as with West Ham and Bolton we could have got points. At the moment it doesn't go for us."

Fulham deserved a more gracious assessment. They went ahead in the sixth minute when McBride exploited poor marking to head in a Jensen corner, and Arsenal players were gesticulating at each other and complaining about lack of communication even before the second goal.

The imprudence of his selection was emphasised when Boa Morte used brilliant skill to flick the ball over his head on Fulham's left, beat Song and cross to the far post where Tomasz Radzinski was too sharp for Flamini. Fulham dominated and only two Lehmann saves and a narrow Jensen miss kept Arsenal in it. Fábregas' introduction improved Arsenal but hope disappeared when Senderos tripped Boa Morte to earn a second caution.

"That's the best performance since I have been here," said Coleman. It left Arsenal 16 points off the top and Wenger will be hurt by the truth about where their season is heading.