Arsenal striker Alexandre Lacazette struck twice as they took control of their Europa League semifinal against Valencia.

Mouctar Diakhaby's header put Valencia in front before Lacazette slotted in Pierre-Emerick Aubameyang's pass.

The Frenchman nodded in Granit Xhaka's cross seven minutes later to make it 2-1 before half-time.

And Aubameyang's late volley ensured Arsenal take a two-goal lead to Spain.

Afterwards, Gunners manager Unai Emery urged calm: "In the first leg we wanted to get a good result, knowing that it would be difficult. After the first goal our response was very good, with calmness and passion. We took our moments and the goals in the first half gave us confidence.

"We wanted to win and not to concede a second goal, but we also had to play. The third goal came at the end and for us it was important, but [the tie] continues to be 50-50."

He continued: "Valencia are a good team. They played with strong players defensively and in midfield. They're strong at set-pieces, they scored and we struggled with set-pieces.

"We'll continue to work on what we can improve, on what we can do better, but generally in the first leg, over the 90 minutes, we can be happy and proud of the players and supporters. Now we will prepare the same for the second leg because we know it will be very difficult."