Andrea Dovizioso says tyre management will be the key factor at Indianapolis

The Italian set steady top six times in both of Friday's free practice sessions on his Honda, but found that grip levels altered significantly as the track's new surface 'rubbered-in'.

He believes that the combination of changing grip levels, hot predicted raceday temperatures of around 30 degrees and Bridgestone's decision to bring its hardest compound rubber to the USA will put rubber management at a premium.

"With more rubber on track [this afternoon], the grip changed quickly and now the main issue is tyre wear," Dovizioso said. "This is typical for new asphalt so we have to manage the tyres carefully, with special attention on the front tyre.

"The key point for the race will be managing the tyres. I hope that conditions will improve again tomorrow as with today's situation it's impossible to finish the race.

"I'm not worried with fifth position as when it was time to push, we weren't able to because we had to keep the tyres for tomorrow so I'm confident that we can be competitive here."

Dovizioso's Honda team-mates Casey Stoner and Dani Pedrosa were first and third overall in Friday's times.