AC Milan manager Clarence Seedorf says players on his club "struggled psychologically to react" against Atletico Madrid.
Milan went out of the Champions League after a 4-1 defeat at the Vicente Calderon in the second leg on Tuesday night.
"You could see after the second goal that the team struggled psychologically to react, as they often do," Seedorf told Sky Sport Italia. "The second goal turned off the light and sapped the energy from the team.
Seedorf again placed blame on the team's substandard fitness levels when he inherited the squad from Massimiliano Allegri in January.
"We've said more than once that the fitness levels I found here weren't optimal, but that's normal to struggle when you have been chasing since the start of the season.
"This moment of difficulty lasted so long that it affected the team. They can react once, but after a second blow they can't get back on their feet.
"In the second half the whole team no longer produced the right level of grit and determination to keep fighting. We sat back too much and in general it was not positive."
Seedorf said Milan must now refocus on Serie A, where the Rossoneri sit at mid-table.
"We analysed the situation together," Seedorf said. "Obviously the Champions League was an important objective for us and economically for the club. We had played well in the first leg and showed in the first half tonight we could play on a par with Atletico, but couldn't be consistent for the whole game.
"We spoke clearly and set objectives in the League, which is our only remaining target. There are 11 games to go and we have some very specific objectives, which are the ones we believe we can get. It's our only tournament, so the squad must feel a realistic sense of what we can achieve.
"We can't throw away the good work we've done. Of course it is very sad to go out of the Champions League and the players are very disappointed, but I am here to lift them up, let them know they can keep working the way they have done and face Parma with the spirit of a side that wants to make up for this setback."