Honda surprised itself with Mexican Grand Prix performance

McLaren's engine partner chose to take penalties for engine component changes on both Fernando Alonso and Stoffel Vandoorne's cars in Mexico, where it felt it would struggle, so they would have fresher parts for the final two races of the season in Brazil and Abu Dhabi.

But McLaren showed good pace throughout the Mexico City weekend, with Alonso fifth in Q1 and declaring he had the best car in the field before going on to finish 10th in Sunday's race.

"The performance was much better than we thought," Hasegawa told Autosport.

"Before we came here, we thought our engine performance was worse than the other teams and the effect from the high altitude would be bad.

"But Sakura has worked hard to create a good set-up for this high altitude, which is why the engine power deficit was much smaller than we thought.

"This gap is smaller. The relative performance is still a bit behind, but we think we can catch up."

Hasegawa pointed to gains made on Honda's dynos at its Sakura base as a reason for its form in Mexico, where the high altitude puts a strain on the engines.

"Previously, we couldn't create a good dyno system to evaluate the high altitude situation," he said.

"But in the last week, we have made improvements in Sakura, regarding the operation of the engine. We made improvements here.

"[Correlation] is getting much better from the beginning of the season.

"It is not 100% copying the circuit situation, so still we need to work but we are almost satisfied with the situation.

"This circumstance, the high altitude in Mexico, is unique, though."