Antoine Griezmann's energy is very important for France - Adil Rami

France centre-back Adil Rami believes that Antoine Griezmann's energy was too much for Republic of Ireland in Sunday's Euro 2016 round-of-16 game.

Rami, 30, had a torrid time as France trailed at the interval against Ireland in Lyon.

But Didier Deschamps' side improved after the break to win 2-1, with a brace from Atletico Madrid forward Griezmann booking them a quarterfinal date with either England or Iceland.

Griezmann's work rate also impressed as he went close to a hat trick and helped ensure that there would be no comeback from 10-man Ireland.

"It doesn't surprise me anymore because I know him," Sevilla defender Rami said of Griezmann after the game. "I play in Spain like him and he's had a really great season.

"He's a player who's difficult to handle for opposing players because he runs everywhere -- I don't know how many kilometres he runs each match.

"He's technical, quick and is very good in the air. I'm happy for him that he got two goals and for us. To have Antoine Griezmann in full confidence is very important for France."

Deschamps tweaked France's tactics at half-time, giving Griezmann a more central role. And Rami, who will miss the next match through suspension, knows how devastating that switch would have been for the Irish.

"It's true that for central defenders it's very tough because he never stops running," Rami said. "You always have to be careful and then he's quick, has good technique and is shrewd."

West Ham playmaker Dimitri Payet also improved after the interval and revealed that France felt they had to up the tempo against an Irish team who had three days less time to recover.

"We had to make them give way," Payet said. "I think we did what was required in the second half for that to happen.

"It's true that in the first half we were less aggressive and there was less energy in our game so that allowed them to defend well."

Payet, 29, admitted that Ireland's physical approach had shaken the French team.

"It's bound to," he said. "We expected guys who never give up and who give you some hits.

"I think that unfortunately in the first half we got annoyed and fell into that game.

"In the second we rectified it, started playing our own game and it paid off."