Gerard Pique was sent off as Barcelona claimed a 3-1 win at Getafe in the Primera Division to maintain their perfect away record.
Pique handled in the area midway through the second half and was shown his second yellow card of the night.
Manu del Moral converted from the spot, but Barcelona were already three goals up at that stage.
The Catalans went in 2-0 ahead at the interval following strikes from Lionel Messi and David Villa.
Pedro then extended Barcelona's lead with a third goal after 64 minutes and the victory never looked in doubt for Pep Guardiola's side, even after they had been reduced to 10 men.
Getafe also finished the match with 10 men after Derek Boateng was sent off with 10 minutes left.
Guardiola handed a start to Javier Mascherano in the defensive midfield role and left Sergio Busquets on the bench.
There was also a place in the starting 11 for Xavi, who has been struggling with an Achilles problem and was not expected to be fit.
While the Madrid derby was occupying most residents of the Spanish capital, a few miles across town in Getafe, the Catalans started at an electric pace.
Villa blasted over when one-on-one with Jordi Codina after four minutes and Messi was denied by the Getafe goalkeeper not long after that.
Pedro then almost opened the scoring after 21 minutes, when Codina struggled to deal with the winger's left-footed drive.
But a minute later, Barcelona were ahead.
Dani Alves found Villa in the area and the Spain striker, with little option to shoot, laid the ball off for the advancing Messi, who beat Codina with a clinical finish at the near post.
Villa then found the net himself after 31 minutes, but saw his effort ruled out for offside.
Three minutes later, however, the former Valencia forward did get on the scoresheet as he latched on to Messi's through-ball and beat Codina with a cool finish.
Victor Valdes made a good save to deny Manu eight minutes into the second half, but there was no way back for Getafe as Pedro struck the third.
There appeared little danger as Codina gave the ball to Daniel 'Cata' Diaz, but Messi charged in to poke the ball off the feet of the defender and into the path of his grateful team-mate, who was left with a simple finish to make it 3-0.
Pique then handled in the box and was dismissed five minutes later.
Manu stepped up to fire home from the spot and give Getafe hope.
Barcelona kept attacking, though, and Messi almost made it 4-1 shortly afterwards.
At the other end, Juan Albin tested Valdes with a fierce drive and Javier Arizmendi saw his effort cleared off the line by Maxwell.
But any hopes Getafe had of making a comeback were dashed with 10 minutes left as Boateng was dismissed for a second bookable offence.
There were chances for both sides after that, but no further goals.
Barcelona now have 25 points from their 10 matches, 12 more than 11th-placed Getafe.