Bridgestone happy with tyres' role in USGP.

Bridgestone has admitted that it was pleased to see its products have an effect on the racing in Sunday's United States Grand Prix, despite suggestions from some drivers that wear rates played a part in their individual results.

The two tyre options were reckoned to differ by around four-tenths a lap - more than at some other races this season - making the decision of when to run the harder compound more vital. However, with graining also being reported on the abrasive Indianapolis tarmac, the choice was further clouded.

Ferrari's Kimi Raikkonen was the only top driver to start on the medium compound and used the softer rubber in his final stint to set the race's fastest lap and put pressure on team-mate Felipe Massa to the chequered flag.

"The soft was a bit more grippy, so it was better," Massa revealed later, "The degradation was not incredible compared to the hard. The hard was just sliding around, so it was difficult to keep the rear on the ground."

Race winner Lewis Hamilton, meanwhile, employed the same soft-soft-medium strategy as McLaren team-mate Fernando Alonso, the pair coming home one-two.

"It was a fantastic result for Lewis Hamilton and I am happy that the tyres had an influence on the race as both compounds of Potenza allowed any strategy," head of track engineering operations Kees van de Grint said, "Not all of the drivers in the points used the same compound for the final stint, and a driver on a single stop strategy [Nico Rosberg] was on for a points finish until he had to retire due to a non-tyre related issue."

Alonso was among those to report graining on his tyres, suggesting that it was enough to preclude an assault on his team-mate's lead.

"When you follow someone, you lose a little bit of downforce and it's difficult to get the tyres in the condition to push all through the stint because you damage them maybe a little bit more when you run behind someone," the Spaniard observed, "I tried in the middle stint, and I was side-by-side [with Hamilton] once, but it was not enough to overtake him."

Asked if the graining was worse this season than in the past, Alonso admitted that there was not too much difference generally, but suggested that the Brickyard had been a special case.

"It seems higher here in Indianapolis than on other circuits," he confirmed, "I experienced it on Friday when I was doing the tyre test. I did ten timed laps with the primes, ten timed laps with the option and, when I did the option tyre, I followed Rosberg for four or five laps. When I arrived back at the garage, the tyres were in very bad condition, so it seems that, when you follow a car, the tyre degradation is much higher, there's no doubt."

van der Grint also appeared unable to resist having a dig at departed rival Michelin when praising the performance of his company's products.

"I am extremely proud that cars on our tyres have won at this circuit for the eighth time," he said, after McLaren added to Ferrari's previous Indianapolis success, "For a company which puts safety first, not only on its road tyres but its race tyres too, to master turn 13 at Indianapolis - the most challenging corner on the calendar - is a real accomplishment. Not only did we overcome the notorious banking, but the high temperatures too, as the tyres' operating temperatures were well over 100 degrees Celsius today."