Fernando Alonso says he knew before the Mexican Grand Prix that he had a problem with his McLaren, but took the start out of respect to the fans.
Alonso and McLaren endured a difficult weekend and the squad detected an issue with his car prior to the race, with insufficient time to undertake a repair.
Alonso took the start from 18th position but soon slowed and pulled into the pits at the end of the opening lap.
"We had an MGU-H rotation speed problem – it was something we spotted on Saturday night, and unfortunately confirmed it in the morning," he explained.
"We didn’t have enough time to replace it, so we were left with two options: to race or not to race.
"We went for the first option, and tried to do as much as we could, out of respect for the amazing fans in Mexico. I really wanted to go to the grid, take the start, and then just see what happened.
"It was only one lap, but, even so, I enjoyed it. At least we tried; it’s always best to try than to give up."