Fernando Alonso has revealed McLaren had two options on Sunday in Mexico; one was not to race while the other was to do so knowing he would only manage a lap or two.
The double World Champion qualified P16 for the Mexican Grand Prix but lined up 18th on the grid due to engine penalties.
However, rather than make up positions at the start he retired after a handful of corners with a loss of power.
Alonso later revealed that McLaren-Honda were already aware of the problem last night but decided to take to the starting grid out of respect to the 100,000 plus fans.
"Yesterday night we spotted a speed problem and this morning we confirmed it," he stated.
"We had two possibilities; retire the car before the start of the race or try our maximum knowing that maybe one or two laps was the maximum we could achieve.
"We did one lap out of respect of the fans who were amazing all weekend.
"We will try to improve next time."
Sunday's DNF was Alonso's eighth retirement of this season, which he concedes has been rather frustrating.
"Yeah it has been very frustrating obviously
"To not even be able to participate in this race in front of this amazing crowd.
"Even if you are last you are at least still on the track. It is very very hard."