Arsene Wenger has heaped praise on Alexis Sanchez after his stunning goal in Arsenal's 3-1 Europa League win over Koln on Thursday night.

The Chilean forward found the net with a superb curling effort for his side's second goal, either side of strikes from substitute Sead Kolasinac and Hector Bellerin.

And Wenger effused over Sanchez's second-half display, while complimenting the impact of Kolasinac after the break.

Arsenal FC v 1. FC Koeln - UEFA Europa League

"Sanchez came alive in the second half," the Frenchman said, quoted by ​Sky Sports. "He is still fighting to come back to his best physically, but Sanchez is Sanchez. He's an exceptional footballer.

"I moved to a four in the second half, [Sead] Kolasinac I think gave us a lot going forward, but as well he pushed Sanchez forward, who played deep in the first half.

"When he had more support on the flanks from Kolasniac he became more dangerous."

Arsenal fell behind inside ten minutes when David Ospina was lobbed by Jhon Cordoba's audacious long-range effort, and Wenger admitted that his side were uncharacteristically lethargic in the early stages.

"I believe we had a little bit of a slow start, our combinations were too slow, and on top of that, we were shocked by the stunner that they scored," he said.

"From then on it was important we did not panic and to keep control of the game. In the second half I believe our team was better balanced better equipped going forward.

"I changed it at half-time, and second half was one-way traffic. It was just a question of time, overall I think we won it in a convincing way."