Lewis Hamilton insisted Thursday that he was not at fault for the lock-up on his Mercedes which robbed him of victory at the Azerbaijan Grand Prix. The world champion was heading for victory on the streets of Baku earlier this month with just two laps left when he ran off the track. He was eventually classified 15th in a race won by Sergio Perez in a Red Bull. Speaking ahead of this weekend's French Grand Prix, Hamilton said his car's so-called "magic brake button" had been accidentally activated which caused the run-off and lock-up. Title rival Max Verstappen in the second Red Bull also failed to score points after a tyre blowout while leading. "I don't even count it as a mistake," said Hamilton. "You can't always be perfect but a mistake is where you drive off the track through missing your braking point or hitting the wall. "But it was an unforced error, really something we had that was sitting there that could have happened at any point and it unfortunately bit us pretty hard." To avoid a similar incident this weekend, Hamilton said "we've just put a shroud around it (the button) just to make sure that you can't accidentally touch it in future, but that's for the short-term". Seven-time world champion Hamilton won the French Grand Prix from pole position in 2018 and 2019. Verstappen has a four-point lead in the drivers' title race while his buoyant Red Bull team head the constructors' championship by 26 points.