Dortmund lost the first game of the quarterfinal 4-0. So, they had nothing to lose on Tuesday. They started attacking Barcelona right away, and this surprised Barcelona.

Barcelona's coach, Hansi Flick, knew Dortmund well because he worked in Germany. He said the fans at Dortmund's stadium would be very loud and excited. He thought the second game would be hard, even though his team was winning by four goals.

I thought this might happen, Flick told Amazon Prime. Today, good job to Dortmund, they played very well. And good job to my team, they are in the semifinals.

Barcelona's main attackers, Raphinha and Robert Lewandowski, did not score in the game. This was unusual for them because they usually score many goals.

Coach Niko Kovac said Guirassy is very important for Dortmund. He said Guirassy is like their 'life insurance.' Guirassy played well in a game and became famous fast. Now, he has scored the most goals in the Champions League this year. Kovac said, 'Serhou needs help from his teammates, like all players who score goals. His teammates helped him today.'

Some people think Dortmund lost the first game of the quarterfinal. Also, their captain, Emre Can, and midfielder, Carney Chukwuemeka, were injured earlier that day and could not play.

For a time, Guirassy made it seem like difficult things could happen.

Guirassy had chances to score before, but he scored from a penalty after the other team's goalkeeper hit Pascal Gross.

Guirassy scored with his head to make the score 2-0 in the 49th minute. Then, Dortmund had a harder time because Ramy Bensebaini accidentally kicked the ball into his own team's goal. Fermín López kicked the ball low across the field, and it hit Bensebaini's foot and went into the goal. This was bad for Dortmund because Bensebaini had helped them a lot just before, helping Guirassy score his second goal.

Guirassy scored his third goal because Ronald Araujo made a mistake. He shot strongly from close to the goal in the 76th minute. Now he is the best goalscorer in the Champions League this season with 13 goals.

This gave Dortmund new hope to win, like when Barcelona beat Paris Saint-Germain in 2017, but Barcelona won in the end.

Barcelona will play against Inter Milan or Bayern Munich in the semifinals. This is the first time they have reached this stage in the Champions League since the 2018-19 season. In another game on Tuesday, PSG also reached the semifinals. They won 5-4 against Aston Villa over two games, even though they lost the second game 3-2.

Barcelona lost a game. This was their first loss since December 21. It was also their first loss in the Champions League since September. The coach, Flick, had lost only six other games out of 50. Before this game, he had won seven games against Dortmund when he was the coach of Barcelona and Bayern.

Dortmund might have to wait a long time to play in the Champions League again.

Last year, the team that was second in the Champions League is now eighth in their league. They have five games left. They need six more points to get into the Champions League next year.