Arsenal boss Mikel Arteta admitted he was surprised to have Rob Holding back for the win at Manchester United.
The defender returned from injury to play a key role in Arsenal’s first Premier League win at Old Trafford for 14 years.
Holding played despite only being involved in one training session ahead of the game.
Speaking at his post-match press conference, Arteta said: “He had one session. We didn’t expect him to be back so quickly.
“Rob has this determination and the willingness all the time to play. He works hard and puts himself in the line if we need him.”
Arteta feels Sunday’s victory should give his players the belief that they are capable of beating anyone in the division.
“I wanted to generate belief and I asked them to be who we are as a team right now,” he said.
“I’m delighted because we played with a lot of courage and big personality.”
United boss Ole Gunnar Solskjaer said: “We didn’t turn up, especially in the first half. That’s what we have to address because we know these boys can be so good.
“We knew that this was the big game this week. And unfortunately in the first half we didn’t play well enough.”