Barcelona won a thrilling Spanish Super Cup final in Jeddah, defeating rivals Real Madrid 5-2.
The German coach referred to the outcome as "unbelievable" because it was Barca's first trophy under her leadership.
After Kylian Mbappe gave Madrid the lead, a powerful Barcelona team responded with five goals before Wojciech Szczesny, their goalkeeper, was sent out in the second half.
Madrid was left wounded and beaten by their bitter rivals in Jeddah, where they were seeking to exact revenge for losing to Barcelona 4-0 at home in the October La Liga Clásico.
Following Mbappe's first goal, Robert Lewandowski gave Barcelona the lead from the penalty spot, Raphinha scored twice, and Alejandro Balde also scored. Lamine Yamal then tied the score.
With a free kick, Rodrygo Goes gave Madrid a response, but they were unable to build on their numerical advantage, and the Spanish and European champions suffered a crushing defeat.
Carlo Ancelotti, the coach of Real Madrid, attributed the crushing loss to his team's subpar defense.
Mbappé's incredible strike on the counterattack gave Real Madrid the lead in the fifth minute, despite a powerful opening effort from Barcelona.
After Vinicius Jr. regained possession of the ball and rushed into the area, the French forward bounded past Szczesny on the halfway line.
Yamal, a 17-year-old winger from Spain, equalized the score with a spectacular solo goal after cutting in from the right and slotting home a low finish inside the near post.
Soon after, Raphinha headed in Kounde's long cross to give Barcelona their third goal, and they scored their fourth just before halftime.
After Yamal and Raphinha joined forces, Balde slid in and slipped past Courtois.
After the interval, Barcelona carried on in the same manner, and Raphinha scored the fifth goal with a deft dribble and finish after Marc Casado had sent him in.
After a VAR review was rejected, Mbappe raced in at the other end and around goalkeeper Szczesny, bringing him down outside the area and reducing the Catalans to 10 men.
Rodrygo, who had already struck the post, hammered the free kick beyond Inaki Pena, Szczesny's substitute.
Jude Bellingham was well set up by Mbappe, but a fantastic challenge from Jules Kounde in stoppage time denied the England international.
During a brilliant solo effort, the French striker also almost scored again, but Pena deflected his shot.
Due to a contentious matter that clouded the semifinals earlier in the week, Barcelona brought in playmaker Dani Olmo for his maiden appearance after he was registered to play for the team on a temporary basis.
But when Barca triumphed in their record-tying 15th Spanish Super Cup, their five-star performance provided a wealth of other discussion points.