Arsenal boss Arsene Wenger praised his side's solidity as they saw off Borussia Dortmund at Emirates Stadium to seal their place in the knockout stages of the Champions League.
The Gunners' erratic form had been highlighted again as they lost 2-1 at home to Manchester United on Saturday -- but there were no such problems this time as Yaya Sanogo's first competitive goal for the club and a superb Alexis Sanchez effort sealed the points with a 2-0 win.
"We had the focus to defend well together," Wenger told Sky Sports. "We had a similar game to Saturday, but we focused really well not to give any chances away."
He hailed Sanchez, who produced another moment of magic for the north Londoners, saying: "He brings unbelievable fighting spirit and his class as well -- he's a mixture of talent and desire."
But he voiced concern at more potential injury problems, with both Sanogo and Mikel Arteta forced off, with the latter a particular worry.
"It doesn't look good -- it's a calf," Wenger said. "It's difficult to take on the chin at moment. You go in to many games and need everyone available."
Defender Per Mertesacker said he was delighted with the resolve the Gunners had shown, saying: "Over 95 minutes we played absolutely solid, and that was key.
"We didn't give them too much, especially in the second half. We've had a few disappointing results, so today was a mental test -- but we are strong enough and now we can continue.
"We are through to the knockout stages, and now we have to focus on the Premier League."