Manchester United boss Erik Ten Hag admits he's been impressed by Unai Emery's impact at Aston Villa.
United host Villa today.
Ten Hag said: "We met him the first game and he surprised us. We were low energy levels so we have to avoid that, but he surprised us with the system.
"Three days after we learnt a lot from that game and we bounced back and had a good win over them.
"Sunday will be a tough game, we're totally aware of it. This team made good progression, but it's up to us, if we're ready for the game, we have the right energy levels, with the right focus, at Old Trafford with the fans behind, then we know we have a good chance to win this game because we know we are very strong."