Arsenal defender Sokratis Papastathopoulos believes Unai Emery has done more for his development in a single season than former mentors Jurgen Klopp and Massimiliano Allegri.
Ex-Sevilla boss Emery could win the Europa League for the fourth time when the Gunners meet Chelsea in the final in Baku on Wednesday.
Getting the better of Maurizio Sarri's side would secure Champions League participation next season and answer some of the critics who have questioned the Spaniard following a fifth-place finish in the Premier League.
Greece international Sokratis has had an intimate view of Emery's methods and rates him above the other high-profile coaches he has played under, including Allegri at AC Milan and Klopp and Thomas Tuchel during his time with Borussia Dortmund.
"He's the best coach I [have] had in my career," the 30-year-old told The Guardian.
"That's because I have improved a lot under him. I play faster than one, two or three years ago.
"I think more and I make better decisions and his coaches do a lot of individual work with us. You can also see that because of the number of young players coming through."
Sokratis is likely to start in Azerbaijan as Arsenal attempt to complete a fine run that has taken them past BATE, Rennes, Napoli and Valencia in the knockout rounds.
They beat Chelsea in the Premier League in January but finished two points behind the Blues in a tight tussle for the Champions League places.
"Chelsea has a good team. Very good players. We respect them. We are not afraid," Sokratis said.
"It's one game. One final. We like to be there. We like to win. We want to play next year in the Champions League."