Defending IndyCar Series champion Will Power has set the fastest time in practice for the title-deciding Sonoma race.

Team Penske driver Power, fourth in points standings, posted a 1:17.48s lap at the 12-turn road course to head Graham Rahal (Rahal Letterman Lanigan Racing) who is second in the points race.

Andretti Autosport stalwart Ryan Hunter-Reay was third fastest ahead of Scott Dixon (Chip Ganassi Racing) who is third in the points race.

Title leader Juan Montoya set the ninth fastest time while his Penske team-mate Helio Castroneves (fifth on the points table) was seventh fastest.

“It was the first time we got to try the new (Firestone primary) tyre,” Power said, who has won three times at Sonoma over the past five years..

“Basically on a long run, it definitely degrades a lot. I think that will create good racing,”

“It was a good session, but tomorrow, obviously, really counts. We’re in a good window. Just go home, study and have a look and see if we can make good changes see if we can go a little faster.”

The only other driver in with a mathematical shot, Josef Newgarden, was 13th fastest.

Montoya holds a 34-point edge going into the 85-lap race which carries double points as well as bonus points for pole (one), leading a lap (one) and leading the most laps (two).

Oriol Servia used the session to become acclimatised to the #25 Andretti Autosport Honda who is driving in a tribute to his good friend Justin Wilson who tragically lost his life a day after suffering head injuries at Pocono last weekend.

Earlier on his out lap, Servia’s machine came to a stop at Turn 2, causing the only stoppage to practice.