Diego Simeone is still astonished by the competitive edge his Atletico Madrid team can find after they saw off Barcelona in the Champions League.

Atletico lost the quarter-final second leg 2-1 at the Metropolitano on Tuesday, but Ademola Lookman's strike proved enough for them to seal a 3-2 aggregate victory.

Simeone's Atletico have reached the Champions League semi-finals for the first time since 2016-17.

They have been eliminated from the quarter-final stage three times, the last-16 stage three times and the group stage twice since their previous last-four appearance.

Atletico fell two goals down inside 24 minutes, and over 14 years into his tenure, Simeone is still blown away by his side's character.

"It has been 14 years and honestly, seeing the team still competing this way is thrilling," he said.

"The players have changed and countless times we have started over again. Now we are back among the top four in Europe.

"We faced a team that plays exceptionally well, with incredible speed, difficult to control. We made a huge effort after going down 0-2, despite some individual errors."

Lamine Yamal's opener, which came in the fourth minute, was the second-earliest home Champions League goal that Atletico have conceded, after Bruno Alves netted for Porto in December 2009 (01:21).

Ferran Torres then made it 2-0 to the Blaugrana, but Lookman hit back for Atletico. The Nigeria international has been directly involved in nine goals (six goals, three assists) in 17 appearances since he made his debut for the club in February.

"It was a game of two halves, really. We stuck in and dug in and went through to the semis," Lookman told TNT Sports.

"As the game is going on, you're playing and moments happen in the game. The pause lets you switch back into gear and we were able to create a few chances.

"We got the goal and we were able to continue in that way in the second half."

Barca had a goal disallowed for offside early in the second half, before Eric Garcia's red card for a foul on Alexander Sorloth helped Atletico get over the line.

"Every time we compete with Barcelona, we understand there is only one way to face them, attack them," said Simeone.

"They had more possession this time; in the previous match, it was more even. If you don't attack them, you lose. They're very good at attacking."

Antoine Griezmann was serenaded by the home fans at full-time, having made his 100th Champions League start, with Karim Benzema (132) the only Frenchman with more in the competition.