Diego Simeone conceded Barcelona were "a step ahead" of Atletico Madrid as they almost pulled off a stunning Copa del Rey semi-final comeback.
Atletico are through to the final of the competition, where they will face either Real Sociedad or Athletic Club in April, but they had to hold on at the end of Tuesday's second leg.
After Atleti won the first leg 4-0 at home last month, Barcelona ran out 3-0 winners in the second, thanks to Marc Bernal scoring either side of Raphinha's penalty, but a fourth goal that would have forced extra time remained elusive.
Having held on against their rampant hosts, Atletico have qualified for the Copa del Rey final for the 20th time in their history, for the second time under Simeone and the first time in 13 years.
Simeone had been expecting a tough test at Camp Nou and was full of praise for Hansi Flick's side and how they limited Atletico's ability to play to their gameplan.
"We knew we were coming to a difficult ground," Simeone said. "They're a team that plays very well.
"We couldn't, and they didn't let us progress in attack to create more plays like [Marcos] Llorente's and [Ademola] Lookman's.
"The third one looked like it was offside, but it wasn't. If Barcelona score goals from set-pieces, it's even more difficult.
"They took away the time we needed to play. At home, we had that time. We played with a higher intensity then. That's why we scored four goals. Today it was harder.
"But I leave with the joy and the great effort of knowing how to suffer. It's part of this competition when it's a two-legged tie.
"The changes were to increase the intensity. They were a step ahead of us. We couldn't break through from the back like Llorente did once. But it was only once. In the first leg, we broke through much more often. When you attack less, against a team that plays well, you suffer more.
"I told [Hansi] Flick they played brilliantly. I hope we meet in the Champions League quarter-finals. I think today, with the score at 3-0, I said: 'This is Atleti'."
Atletico's last piece of silverware was their LaLiga victory in 2020-21, while they have not won the Copa del Rey since 2012-13, which is also the last time they reached the final.
And Koke noted how important it is for Atleti to end their wait for a trophy, especially after a difficult semi-final.
"We haven't won a title in four or five years. We wanted a final for our fans," Koke said. "We were excited about the Copa. Luckily, we were able to reach the final.
"We knew we were going to suffer. We had chances in the first half to kill the game, but then they scored the second, and you have to suffer and resist. The team did what it had to do to get through the tie."
The Atletico captain was also full of praise for Barcelona's Pedri, who won possession a game-high 14 times, won 12 of his 21 duels and played 41 passes in the final third, while also creating two chances.
"Barca is a fantastic team. The young lads are flying," he added. "Pedri, if he's not the best in the world, is certainly one of the best.
"It's not easy coming to play at Camp Nou. With all the atmosphere that's been created... that makes a difference.
"In the first half, especially, we were able to put the game away. It's the defeat that has brought me the most joy.
"Pedri is a machine. We're so lucky he's Spanish. He's the present and future of Spain. He'll bring a lot of joy to Barca and the national team. Besides being a great footballer, he's a spectacular guy."