Europa League winners Atalanta are significantly less competitive at the moment compared to just a few months ago, coach Gian Piero Gasperini conceded.

Gasperini led Atalanta to victory in the Europa League final in May with a 3-0 win against Bayer Leverkusen in Dublin, having impressively knocked out Liverpool at the quarter-final stage.

His side are set to face Champions League winners Real Madrid in the UEFA Super Cup in Warsaw on Wednesday, but Gasperini warned fans of the Bergamo club not to expect a strong start to the season.

"It's inevitable that it's turned out like this, but at this moment, the season has already become complicated," he told the local newspaper, l'Eco di Bergamo.

The 66-year-old coach confirmed that central midfielder Teun Koopmeiners is set to join Juventus and is no longer training with the first team.

"We've had two very serious injuries, two cruciate ligaments in practically three games with [Giorgio] Scalvini and [Gianluca] Scamaccama, and then the Koopmeiners situation.

"Three technically gifted and economically valuable players for the team and club."

However, Gasperini was hopeful new recruits would be found before the end of the transfer window.

"Honestly, I'd hoped to find myself going into a game as important as the European Super Cup with more of a defined and settled team, having improved with new additions after the Europa League final victory," he said.

"But instead, at this moment, we are down to the minimum, even if I am sure that the club will provide in some way before the end of August."

Atalanta start the Serie A season at Lecce on August 19.