Their manager's warnings about complacency having gone unheeded in one Champions League away game, Arsenal's players should at least be better prepared for the next one. A flattering 5-1 win at home to Shakhtar Donetsk was never going to be a good guide to the return in Ukraine on Wednesday, and a 2-1 defeat adds extra pressure to the next European task.
That is a visit to Sporting Braga, who were brushed aside 6-0 at the Emirates but have since beaten Partizan Belgrade twice to haul back to within three points of the leading pair. In Portugal, then, Arsène Wenger's side will need greater levels of the "concentration and urgency" which he agreed were lacking in Donetsk after an early goal from Theo Walcott.
Walcott, praised earlier in the week by the manager as a potential new Thierry Henry, took his chance well with a burst of acceleration that the old Arsenal hero would have admired, bringing him a seventh goal in eight games, which is as many as he has ever scored in a full season.
An outstandingly open game then followed in Donetsk, with the home side recording 14 shots on target and the visitors nine. For Arsenal those figures showed both how wasteful they were – Walcott and Sebastien Squillaci being the worst culprits – and how easily Shakhtar opened up a defence that was shielded only by two teenagers in Craig Eastmond and Jack Wilshere.
In the 17 minutes before half-time Eastmond headed an own goal and Gaël Clichy made an error that allowed what turned out to be the winning goal. It was scored, almost inevitably, by Eduardo da Silva, who left north London in the summer.
"I scored at a good time, in the last minute of the first half," he said. "That gave us confidence and we played very well in the second half. Everyone saw they had a lot of chances, but we closed them down well. Shakhtar are a football club moving in the right direction."
That progress should take them into the Champions League's last 16, which Arsenal still should also reach for the 11th season in a row. With the four midfielders missing on Wednesday all due to return soon, including Cesc Fabregas, the Gunners go into a run of four Premier League games, starting at home to Newcastle on Sunday and finishing with the derby against Tottenham three days before the Braga trip on 23 November.