One win in eight matches is form that has had Kevin Keegan pilloried. It is a streak that gets managers the sack. It is not the sort of run that Arsène Wenger expects to have to explain and, to be fair to him, he has not needed to for nine years.

Arsenal’s worst sequence in almost a decade is all the more remarkable given that the solitary victory was an unforgettable one, at the home of the European champions, AC Milan.

It did not take a man with Wenger’s wisdom to detect the problem at Stamford Bridge yesterday, although it was still reassuring to hear it from the “Professor of the Emirates”. He said: “We conceded an easy goal against Middlesbrough, an easy goal against Aston Villa. Defensively, we lost control of the game. We got caught when Nicolas Anelka came on to the long balls and the physical battle. We lacked defensive authority.”

This was a particularly worrying omission, given that, in a young team, Kolo Touré and William Gallas are two of his more experienced, established players. If he cannot rely on them, he is in trouble.

Wenger declined to discuss individuals, but it seemed obvious to whom he was referring when he said: “We need to be more serene.” Just when Arsenal have needed a strong leader, Gallas has been acting like a man with a screw loose. He was erratic once again yesterday, his hopelessly mistimed header leading directly to Didier Drogba’s first goal.

Never comfortable under the high ball, Gallas had struggled to shackle the big striker all afternoon. And as the captain floundered, Touré compounded Arsenal’s defensive disarray with his own ill-judged tackle before the second goal. No one is saying that it is easy to subdue Drogba and Anelka, but Wenger did not deny that his defence had floundered.

“We have to show we are strong,” Wenger said, but the title is surely now beyond them. The Frenchman all but admitted it when he said that he was worried only about where there next victory would come from. With only a week before they face Liverpool in the Champions League quarter-final, first leg, his players badly need a restorative win away to Bolton Wanderers, if only for morale.

The Champions League appears their only chance of silverware, although a fourth Premier League title for Wenger had seemed unlikely even though Arsenal had been in the top two from the first week of September until Drogba’s winner yesterday. Their peaks of form have been as high as any of their rivals, but there is a fragility about all of Wenger’s constructions; this one more than any, given the youthfulness.

For more than an hour, they played some lovely football yesterday. Cesc Fàbregas, who must be competing with Fernando Torres to be Cristiano Ronaldo’s bridesmaid in this season’s individual honours, played the most fabulous pass of the afternoon.

“The spirit was right, the mentality was fantastic,” Wenger said. “All that was left for Chelsea was to play long balls and, suddenly, we were vulnerable.” Worrying for Arsenal, it was as simple as that. In that last statement – and in owning up to his team’s soft centre – Wenger may just have written Rafael BenÍtez’s tactical instructions for next week’s quarter-final.

Having seen the title slip from his grasp, it was probably as well that Wenger missed Ashley Cole cupping his ears in celebration. This week of all weeks, you might have thought that Cole would have kept his head down.