Roy Keane and Jamie Carragher have already told Manchester United what they can expect from Villarreal's Unai Emery in the Europa League final.
Having won the competition three years in succession with Sevilla, the Spaniard and his team are standing in the way of Ole Gunnar Solskjaer picking up his first trophy as United manager.
Emery endured an ill-fated 18-month spell in charge of Arsenal in the Premier League.
However, the 49-year-old head coach remains well-respected in La Liga and, of course, has unrivalled pedigree in the Europa League, too.
It was against the Gunners, incidentally, that Villarreal booked a place in the Gdansk showpiece alongside United, who overcame Italian opponents Roma courtesy of a resounding 8-5 aggregate verdict.
Solskjaer's men are favourites to reclaim the competition they last won in 2017 - although Emery has since reached the final with Arsenal, only to be beaten 4-1 by Chelsea in May 2019.
He didn't last too much longer at the Emirates Stadium, either, having replaced Arsene Wenger after his 22 years at the Arsenal helm.
Shortly before he was sacked by the Gunners, in November 2019, former United captain Keane and fellow pundit Carragher shared their thoughts on the Spaniard while analysing a game for Sky Sports.
Carragher said: "When he came in, I thought Arsenal wanted a manager who was going to be a little bit different from Arsene Wenger; more organised, a bit more pragmatic. I think that's what Arsenal fans thought they were getting. If you look at his results, it's all over the place. You talk about them bringing in a pragmatic coach, it looks like they brought in a basketball coach.
"They are the team, at the moment, that everyone wants to watch - probably except Arsenal fans. I said the same about Liverpool a few years ago under Jurgen Klopp; entertaining, goals, end to end games. Everyone loves it, except their own supporters. What is Unai Emery? What are we getting? We are not getting what we thought we were getting, initially."
Keane added: "He is clearly a very, very good coach with a great reputation. He's won trophies previously, but we still go back to the problems Arsenal have. No matter how good a coach you are, if you have got players in your back four who can't defend, you are going to give up shots and you are going to give up goals. I still think this spine of Arsenal is very weak.
"No matter what a good coach he might be, those weaknesses are there. He won't be able to fix that. When you're on about these experienced players, they aren't going to change."