Italy head coach Roberto Mancini criticised fans in Milan for choosing to jeer goalkeeper Gianluigi Donnarumma in 2-1 Nations League semi-final loss to Spain, saying the national team comes above all else.

Donnarumma left Serie A outfit Milan for Ligue 1 giants Paris Saint-Germain on a free transfer in the off-season, prompting some fans to jeer him every time he touched the ball upon his return to San Siro for the first time since the move.

The 21-year-old star was hardly impacted by the frequent jeers on Wednesday and whistled although he fumbled a routine take from Marcos Alonso's shot on to the post in the first half.

"For sure [Donnarumma] wasn't happy about the whistles during the first half but what could we do?," Mancini said during his post-game news conference.

"We are all adults and we have to accept also this situation and in the end I think Gigio despite that played a good game. It certainly won't have pleased him, just as it did not please us. Gigio did well."

Mancini added: "Donnarumma played for Italy and it was not a club game. This situation could have been put aside for one night and [they could have] whistled [at him] in a possible PSG vs Milan [match]. Italy are Italy and come above all else."

The defeat ended the European champions' record 37-game unbeaten run, as well as their bid to add the Nations League title to their Euro 2020 crown.

Italy's undefeated streak dated back to September 2018, when they went down 1-0 to Portugal in a Nations League group game in Lisbon.

"It would have been better not to suffer this defeat but we knew that sooner or later eventually we would have to lose a game," Mancini said. "It is better for it to come tonight than in the final of the Euros or the World Cup.

"I believe though that this game makes us even stronger despite the defeat and allows us to understand that we are truly a great team."

Italy's hopes of victory were not helped by captain Leonardo Bonucci's second yellow card in the first half, with Ferran Torres' two goals coming either side of his 42nd-minute sending off.

Bonucci was initially booked on the half hour for dissent before a second yellow card for a raised elbow in an aerial challenge with Sergio Busquets.

"About Leo, he was a bit naive tonight and in this type of game you cannot make these mistakes," Mancini said.

"It's true that the red card had an impact on the rest of match. Until that moment Spain had more ball possession which is what they are used to. We were in a bit of difficulty, but we could have ended the first half at 1-1.

"We should not have conceded the second goal at the end of the first half. We should have paid more attention for their second goal. It's already difficult to face Spain with 11 players but when you are one man down it becomes much more complicated."