Arsenal boss Arsene Wenger has paid tribute to "exceptional footballer" Alexis Sanchez after the Chilean scored his first goal of the season in Thursday's 3-1 win over FC Koln in the Europa League.

Sanchez was widely expected to leave Arsenal in the summer, but the Gunners refused to sell the attacker to Manchester City despite a number of offers arriving from the Etihad Stadium.

The former Barcelona attacker was back in Wenger's starting XI for the European tie in London, and he scored Arsenal's second of the night as the Premier League outfit came from behind to win.

"Sanchez came alive in the second half," Wenger told reporters. "He is still fighting to come back to his best physically, but Sanchez is Sanchez. He's an exceptional footballer."

Sanchez, who is now in line to start Arsenal's trip to Chelsea in the Premier League on Sunday afternoon, will see his contract at the Emirates Stadium expire at the end of this season.