McLaren driver Lewis Hamilton described his retirement from the Singapore Grand Prix with a gearbox failure as “heartbreaking,” but insists his fight for the Formula One drivers’ championship is not over yet.

Hamilton started on pole Sunday and led until lap 22, when his car – which had been leaking gearbox fluid for three to four laps beforehand – finally ground to a halt, having repeatedly dropped into neutral.

“It’s heartbreaking not to have finished the race today,” Hamilton said. “We definitely had the pace to win this weekend. In fact, before I retired, I was cruising.”

With six races to go, Hamilton trails championship leader Fernando Alonso by 52 points, having dropped from second to fourth in the standings.

“It’s going to be hard to close the gap to guys like Fernando (Alonso) and Sebastian (Vettel), especially when they keep finishing race after race, but I’ll never give up,” Hamilton said.