The Chilean scored twice as the Gunners beat Louis van Gaal's side 3-0 at the Emirates. However, he was substituted in the 80th minute for Kieran Gibbs, clutching his groin and went straight down the tunnel with physio Colin Lewin.

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After the match, manager Arsene Wenger admitted he was concerned about the injury. He said: "He has a little groin problem.

GETTY Alexis Sanchez is back to form for Arsenal

"Unfortunately he goes to Chile. You cannot stop him from going to Chile and he loves so much to play for his country and he will play against Brazil [on Friday] and Peru [next] Tuesday so the game at home against Brazil he will not want to miss. "Hopefully he will come back in good shape."

GETTY Alexis Sanchez holds his groin after being forced off against Man United