Sergio Perez has revealed the cause of his disastrous start to the Belgian Grand Prix after recovering to finish second to team-mate Max Verstappen.
The Mexican started second at Spa Francorchamps but was swamped by Fernando Alonso and the two Mercedes drivers on the short run to La Source.
But despite dropping to fourth, a brave move around the outside of George Russell at Les Combes and a crash between Alonso and Lewis Hamilton combined to quickly undo the damage.
Reflecting on the "bit of chaos on lap one", Perez explained the cause of his poor start.
"I think there was something with the clutch," said Perez.
"As soon as I dropped, I just went straight into wheelspin and here it's very penalising, the tarmac is really rough at the start.
"I think normally here if you get a bad start it's probably one of the worst places to get it because the tarmac is so rough at the start."
Verstappen "on another level"
Verstappen set the fastest time in qualifying but was relegated to 14th through a back-of-the-grid penalty for using power unit components beyond the prescribed limits for the season.
But he put on a scintillating display to score a ninth victory of the season and extend his championship lead to 93 points.
"They got the car was certainly the fastest today," added Perez.
"And especially Max was very impressive. The whole weekend, especially come the race, he was just on another level today.
"So that's great, great to have, you know, but I think it's very track specific. I think when we are at Zandvoort, we will have the Ferraris and Mercedes back into contention."