Arsenal goalscorer Jack Wilshere concedes his side need to regroup if they are to make sure of their qualification from a highly competitive Champions League Group F.

Wilshere scored both goals as the London club defeated Marseille 2-0 to remain top of the standings on 12 points, while Borussia Dortmund's 3-1 win over Napoli left the Germans tied on nine points with the Italian side. The England midfielder was on the scoresheet within the first minute before he added his second midway through the second half.

"It was strange as [anything] in the first 10 seconds," Wilshere said. "We lost the ball and they had a chance and we broke really well and got in front and got a great start. We created a lot of chances tonight. We should have [scored more]. We played great and got behind them."

Arsenal travel to Naples for their final group game knowing they have a three-goal cushion, and Wilshere is refusing to take anything for granted. "It's a tough game, at home they are a very good team. They've got great fans," he said. "We're not through yet - we have to regroup again. It's a tough group, but we will go again."

Chelsea also qualified for the knockout stages despite a limp performance as they were beaten by Basle for a second time in Group E. Mohamed Salah's fine goal three minutes from time earned Basle a deserved 1-0 victory at St Jakob Park and completed a double over Jose Mourinho's Chelsea, who had travelled to Switzerland needing just a point to advance and a win to claim top spot in the pool. However, Schalke's goalless draw at Steaua Bucharest means Chelsea, on nine points, advance to the last 16 ahead of the December 11 meeting at home to the Romanians.

"It was a bad performance that deserved a defeat," said Mourinho. "I didn't like anything we did from the very first minute. We made a defensive mistake immediately and the team I think only had a bit of control in the second half. I felt the players were tired and paid the price for the recent international break."

Chelsea, who have nine matches next month, last season suffered the ignominy of becoming the first winners to exit the tournament at the group stage in defence of their title, before responding by beating Basle in the semi-finals en route to winning the Europa League. This season, in the premier tournament, Basle have exacted a semblance of revenge. Murat Yakin's side were out to prove their win at Stamford Bridge was not a one-off as the Swiss sought a place in the knockout stages, or at least the Europa League. Basle are second in Group E on eight points while Schalke are third on seven points.