McLaren believes stockpiling Honda F1 engines has paid off

McLaren targeted the final two grands prix of the year as races that would prove more favourable to its package than other venues, so it took grid penalties in the preceding events to add fresh power unit components to its available pool for the remainder of the campaign.

In Brazil Alonso used one power unit on Friday and changed to another on Saturday without penalty, and he was able to start sixth and run without problems through the race to an eventual seventh place.

"We obviously took a lot of energy penalties before to try to protect Brazil and Abu Dhabi," Boullier told Autosport.

"We used a lot of engines before just to make sure we had fresh parts. You have to try something, and we decided to protect some mileage.

"In Mexico we were more competitive than expected, and [in Brazil] we had a good race as well. It was good to have a troublefree weekend."

Boullier also praised Alonso for the way he raced in Brazil, despite the obvious handicap of poor straightline speed, staying in touch with the Mercedes-powered Williams of Felipe Massa.

"He managed very well the way he was using the energy of the car, cutting off in the unnecessary part of the track, and using more in the straightline," he said.

"He tried to manage it himself a lot, and did a very good job. The plan was to stay in the DRS [range] of Massa to protect ourselves, this was the only way.

"He was able to [fight] a little bit, and hopefully next year he will be able to do it at every race."