Gian Piero Gasperini says Atalanta face an uphill battle in the return leg of their Champions League knockout phase playoff against Club Brugge, after they were beaten 2-1 on Wednesday.

Mario Pasalic had restored parity shortly before half-time for Atalanta, whose slow start to the match was punished by Ferran Jutgla 15 minutes in.

However, Brugge were awarded a soft penalty in stoppage time for a foul on Gustaf Nilsson by Isak Hein, whose hand appeared to brush against the Swedish striker's face before he tumbled to the ground when both chased after the ball.

It was Atalanta's first defeat in their last 15 European away games (won eight, drawn six), while they suffered their first knockout loss on the road in Europe since March 2021.

Gasperini acknowledged it would be a challenge to reverse their fortunes when they welcome the Belgian champions.

"It will now be a feat, you have to win 2-0 against a good team," he said.

"We will have to expose ourselves a lot more, otherwise they will have half an hour of possession with the goalkeeper. It will be difficult to win by two goals; tonight's match needs to be analysed.

"We started badly, but then we grew. You can't always be at your best and there are also the opponents, but in the second half the sensational opportunities were ours. In the end, we lost."

Nilsson struck the Champions League's first 90th-minute winning penalty scored by a substitute since Eric Choupo-Moting struck for Schalke against Sporting CP in October 2014. On both occasions, the opposition goalkeeper was Rui Patricio.

Gasperini was left to rue that late spot-kick, leaving Jan Breydelstadion frustrated by the task ahead of his team.

"It's a tragedy that we are infecting football [like that]," Gasperini told Sky Sports after Wednesday's game. "Listening to footballers and coaches, they all have a completely different idea of ​​fouls.

"Everyone dives to steal and win a yellow or a penalty. Football is now going in a direction that has nothing to do with the game. We accept it, but I don't know the rules any more, and I certainly don't like it."

Atalanta midfielder Charles De Ketelaere, who left boyhood club Brugge for AC Milan in 2022 before moving to Bergamo a year later, also rued the game's late events.

"If you ask 100 people if it was a penalty, no one will say yes," he said. "[Playing here was] beautiful, I thank everyone for the warmth. But it hurts to lose at the last minute like this."

Team-mate Marten De Roon said the focus should now shift to preparing for the return match.

"It's useless to talk [about the penalty], those who follow football know that it is not a penalty," he said. 

"Let's leave it alone, we have to look at our performance, which was not of a high level. [We were] better in the second half, [but] we seemed a bit tired and this is the analysis we have to do to improve and try to get through the round."