Arsenal academy chief Per Mertesacker says manager Unai Emery has re-energised the club.

It's just over 12 months since Arsene Wenger waved goodbye and the north Londoners have taken time to adjust.

“Going away from Arsene meant there was a leadership void. It was almost the case that Arsene decided everything," Mertesacker said.

“Now it's more spread out. We have brought in Edu, two CEOs, plus myself and a new manager.

“The club has undergone a ­massive change and everyone still needs to find their feet but Unai is more focused on the first team and the football side. He's not as involved as Arsene was in strategic issues. There's a shift in leadership.

“He brings a different kind of energy. You could see the shift from Arsene to Unai. It was new. Everyone was energised by a new start.

"This isn't being negative but you could smell that it needed a new start. There was a difference in training. You could see that after having one manager for such a long time there was a positive energy about the place.

"With the arrival of Edu as sporting director it has all been very positive. We want to build on that momentum. I feel there's some momentum building up. You can see energy about the place."