Eric Boullier has revealed that McLaren-Honda was forced to down-tune Fernando Alonso's power unit in last Sunday's Mexican Grand Prix.

McLaren's race weekend in Mexico was a fairly underwhelming affair with its drivers racing out of the points as Jenson Button and Alonso finished respectively 12th and 13th.

"Clearly, when you qualify 11th and 13th, as we did, there isn’t much to shout about when you manage to convert those starting positions to only 12th and 13th,” acknowledged Boullier.

"But the race was a tough one for us, for many reasons. First, the Autódromo Hermanos Rodríguez is a decidedly difficult circuit on which to overtake, as a result of which our drivers were held up behind Carlos’s [Sainz] Toro Rosso for many laps.

"Second, we were forced to down-tune Fernando’s power unit during the race, which obviously handicapped him to some extent and third, there was a delay during Fernando’s second pit-stop, which lost him a further two or three seconds.

"These things happen – that’s racing – but it’s always frustrating for driver and team alike when they do."

McLaren is obviously hoping for better fortunes in Sao Paulo next week at a venue which historically has been one of the best for the Woking-based squad."

"From here we move on to Sao Paulo, Brazil, whose famously undulating Interlagos circuit will present a very different set of challenges.

"Having won the Brazilian Grand Prix no fewer than 12 times in our history, which is more than any other team, we hope to fare better there than we did here, although a 13th Brazilian Grand Prix victory will of course be out of our reach. But we hope points will be possible."

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