Arsenal manager Arsene Wenger praised the "remarkable" Alexis Sanchez for his performance in the 1-1 draw against Manchester United.
Despite concerns over a thigh injury while Sanchez was away on international duty with Chile, the attacker played 90 minutes at Old Trafford on Saturday.
Wenger was surprised by what the 27-year-old produced so soon after returning from Chile duty.
"I chose him because Alexis is a guy who can take people on and I knew that would be a quality that would work," he said.
"He is good on the counter-attack, good in short spaces as well. He's always a player who is not scared of anybody.
"He played very well in the first half but we didn't give him enough service in the second half because we dropped off too much and we played too many balls in our own half. We didn't give him enough support by coming out more.
"For a guy who played a decisive game on Wednesday morning, and then travelling after, it's remarkable."
Olivier Giroud scored a late equaliser for Arsenal against United, who had gone ahead through Juan Mata.