“I think he's done a fantastic job,” he said. “I have to say he's a manager that I admire a lot. I've studied his teams for a lot of years.
“Of course, I (when on the staff at Old Trafford) came up against his teams at Arsenal whenever he was manager there and a few times against Villarreal.
“He built a fantastic team at Villarreal with a lot of same sort of ingredients from a technical level as he has with this Aston Villa team. He's built a very good side.
“I really enjoy watching them play. We share some principles in terms of how both teams are set up. But they're executing to a fantastic level at the moment and they have done for the last more than 12 months.
“It'll be a great test for us. We're looking forward to it. We feel like we know the opposition pretty well. It's up to us now to do everything we can to make it a really difficult game for them.”
McKenna admits he's long been an admirer of Emery.
“Maybe not surprised, he's done a fantastic job, no doubt about it,” he continued. “I think they have a good squad, good athleticism and good profiles in the squad and had invested well in the squad before Unai arrived.
“I think he's proven at so many clubs in his career and I think the job he'd done at Villarreal, I’d say from a tactical point of view there's a lot of similarities between his Aston Villa team and his Villarreal team.
“We came up against him a couple of times and he took them to win the Europa League (in 2021, beating Manchester United then coached by McKenna on penalties in the final) and to deep in the Champions League.
“He showed again the ability to mould a team that can perform really, really well with the ball, a fantastic structure on and off the ball, really, really clear on their patterns of play and how they look to penetrate.
“And I've seen up close how well he's done with that Villarreal team and I think the ingredients that he's put into the Aston Villa team are similar, just probably with a higher athletic calibre of player.
“So, no big surprises, top manager, always a good test to have to prepare a team against his sides and a really good challenge, and I'm looking forward to it.
“We've had a good time to prepare for this game, it doesn't make it any easier, but I think everyone's clear with their threats, what we're going to have to do to limit them and also where we think we can go and hurt them and we'll try and impose as much of that as we can on Sunday.”