Cesc Fabregas made his Barcelona debut as a late substitute and helped the Catalans beat Real Madrid in a stormy Spanish Super Cup at the Nou Camp.
Fabregas, who signed from Arsenal on Monday for about £35m, came on as an 82nd-minute substitute as his new club took the tie 5-4 on aggregate.
Lionel Messi hit a late winner in a second leg that witnessed three red cards late on.
There was also an ugly melee on the sidelines before the final whistle.
Real Madrid full-back Marcelo received a straight red card for hacking at Fabregas in injury time.
Real Madrid coach
“I have been polite and played like a man and not fallen to the ground at the first touch”
Then, after both sets of players and their benches squared up on the sidelines, Real's Mesut Ozil and Barcelona striker David Villa, who had both been subsituted, were shown red cards.
"Marcelo got a red card because we all know what happens after tackles in certain areas of the pitch," said Real Madrid coach Jose Mourinho.
"It was a spectacular game from the first to last minute. But from the first minute of the second half, and I don't criticise it because I know people do it, the ball boys hid the balls.
"It happens with small teams when they find themselves in difficulties."
Fabregas only played a small part in a dramatic match, but said: "It's a great moment, especially against Real Madrid. It's the biggest derby in the world and I am very happy to be a part of it."
After the first leg at the Bernabeu ended 2-2, Barcelona twice went ahead in the second leg - through Andres Iniesta and then Messi - but they were pegged back first by Cristiano Ronaldo, before Karim Benzema looked to have forced extra-time by making it 2-2.
Messi celebrates scoring the winner with new team-mate Fabregas
However, a Messi volley two minutes from time sparked scenes of wild celebration as the European champions clinched the first trophy of the new season.
Then came the incident that led to the dismissals of Marcelo, Ozil and Villa.
Mourinho also got involved in the bust-up, appearing to try to put his finger in the eye of Barcelona assistant coach Tito Vilanova.
When asked about the incident, Mourinho replied: "I have been polite and played like a man and not fallen to the ground at the first touch. I don't know who Vilanova is."
The bad feeling continued after the match, with Barcelona midfielder Xavi saying: "Real Madrid should be concerned about the image it is giving, it's very damaging.
"Marcelo's tackle has no place in football. Totally shameless, a real shame for football in general this image generated by Real Madrid."
His team-mate Gerard Pique added: "Mourinho is destroying Spanish football. It's not the first time and it's always a number of players and the same ones so there has to be some way of stopping them. I hope they adopt the necessary sanctions."
And after several ill-tempered matches between the teams last season, Barca coach Pep Guardiola said: "The images will speak for themselves. This is going to end up badly if it isn't stopped soon."