After losing the first game of the quarterfinal 4-0, Dortmund had nothing to lose on Tuesday and attacked Barcelona from the start, which made the visitors feel unsure.

Barcelona's coach, Hansi Flick, knows Dortmund well from his time in Germany and has often won against them. He said he expected a difficult second game because of the strong home crowd, even though his team was already four goals ahead.

"I felt a little that something like this would happen," Flick said to Amazon Prime. "Today, we must congratulate Dortmund; they played well, and congratulate my team; they reached the semifinals."

Barcelona's main attackers, Raphinha and Robert Lewandowski, who had scored a lot of goals in the Champions League this season (12 and 11), had a very quiet game. They did not get close to scoring, and Raphinha's weak shot was easily stopped by the goalkeeper.

Guirassy is like Dortmund's "life insurance," said coach Niko Kovac after a game where Guirassy became famous quickly and is now the top scorer in the Champions League this season. "Serhou only needs his teammates to help him, just like any forward, and they did that today."

Some people would say that Dortmund lost the quarter-final in the first game, and also their captain Emre Can and midfielder Carney Chukwuemeka couldn't play because of injuries that happened earlier that day.

For a while, Guirassy made things that seemed impossible happen.

Guirassy had opportunities he didn't score in the first game, and missed a few more chances early in Tuesday's match. However, he scored perfectly from the penalty kick in the 11th minute after the Barcelona goalkeeper Wojciech Szczesny ran into Pascal Gross.

Guirassy scored with a header in the 49th minute to make it 2-0, and then an own goal by Ramy Bensebaini made it much more difficult for Dortmund.

Guirassy used a mistake by Ronald Araujo to score his third goal with a strong shot from close by in the 76th minute. This goal made him the top scorer in the Champions League this season, with 13 goals.

This gave Dortmund new hope of making a great comeback in the Champions League, like Barcelona did against Paris Saint-Germain in 2017, but Barcelona won in the end.

Barcelona will play against either Inter Milan or Bayern Munich in the semifinals. This is the first time they have reached the last four of the Champions League since the 2018-19 season. In the other game on Tuesday, PSG reached the semifinals by winning 5-4 in total against Aston Villa, even though they lost the second game 3-2.

Barcelona lost for the first time since December 21. This was their first loss in the Champions League since September. It was also only the seventh loss in the 50 games since Flick became coach.

Dortmund might not hear the Champions League anthem in their stadium for some time.

Last year, the team that came second in the Champions League is now eighth in their league, the Bundesliga. There are five games left. They are six points away from the top four teams, who can play in the Champions League next year.