Arsene Wenger happy with a 3-0 win over Manchester United

Arsene Wenger (R) gestures towards Arsenal's Welsh midfielder Aaron Ramsey during the English Premier League football match between Arsenal and Manchester United at the Emirates Stadium in London on October 4, 2015. AFP PHOTO

Arsenal boss Arsene Wenger was delighted with his side's response to their Champions League defeat in midweek, as they comfortably saw off Manchester United at the Emirates.

Two first-half goals from Alexis Sanchez, either side of a Mesut Ozil strike, shot the Gunners into a 3-0 lead, one they maintained for the rest of the 90 minutes.

Sanchez opened the scoring with an intricate flick after neat build-up play between Ozil and Aaron Ramsey, before the German swept home left-footed from a Theo Walcott pass.

The Chilean then bagged his second in emphatic fashion, smashing into the top corner after cutting in from the right hand side, past the despairing dive of David De Gea.

Wenger praised Walcott's display, and the application of his side as a whole, after their midweek disappointment.

"We started strong and pressed high," the Frenchman told Sky Sports. "We got quick transition and when we do that, we can score goals. We know that.

"After that we were disciplined and focused, and defended well together.

"It was the most committed I have seen Theo Walcott for a long time. It took him time to recover from his injury, but his performance today was outstanding.

"Let's not forget - we won 5-2 at Leicester last week. We are on a good run in the Premier League. We lost on Tuesday and the performance wasn't disciplined enough.

"The difference was focus. In the Champions League, maybe we subconsciously didn't work as hard. That won't be a problem against Bayern Munich, but it was against Olympiacos.

"We are second in the league and two points off top. We have played great games, winning four times away at difficult places. I have never managed a team who plays all season at the same level."

Wenger was asked about Petr Cech's display, who was impressive as he kept a clean sheet, being restored to the side after being rested in midweek.

The Frenchman agreed his goalie played well, but was once again unwilling to discuss his policy of rotating his goalkeepers for cup fixtures.

"Cech had one crucial save off Martial in the first half with his feet, and he played very well," he added. "If we're coming back to selection - I will stop that now, definitely.

"You always need to win big games. I have played enough in my life to now that it is vital for confidence.

"But you have to back it up with the next performance. We have to be at the same level, and pray everyone comes back fit from the international break."