As Will Power said, the battle for this year's IZOD IndyCar Series championship is coming down to the "nitty gritty."
With three races to go in the season -- including this weekend's GoPro Indy Grand Prix of Sonoma (Sun., 4:30 pm ET, NBC Sports Network) -- Power holds a slim five-point lead over Ryan Hunter-Reay, with Helio Castroneves (-26) and Scott Dixon (-28) not far behind in third and fourth place.
But Power will indeed be the man to beat this weekend at Sonoma, where he's won the last two IndyCar events. He led Friday's practice session with a lap of 78.6887 seconds in the No. 12 Verizon Team Penske Chevrolet, which was followed by Penske teammate Ryan Briscoe and his 78.8782 second lap that was good enough for P2 on the charts. Simon Pagenaud was third-fastest on the afternoon.
"We took the top three spots in the race last year and 1-2 today, so Team Penske definitely has had good success here in the past," said Power. "We'll look at our notes and try to go faster tomorrow. We'd really like a pole position to keep moving forward in the Championship race and we'll see if we can do that [Saturday]."
The man chasing after him, Hunter-Reay, admitted that Sonoma has been Penske turf and that the Northern California road course hasn't been the best place for his Andretti Autosport team in the past. But considering how the championship has changed drastically on a race-to-race basis as of late, RHR knows he's right in the hunt.
"Every race is going to be pivotal," the American driver said. "We came into Mid-Ohio, the last race, leading by  points, and now we are trailing by five. It can swing quickly. We had an engine issue there at Mid-Ohio, which sidelined us.
"Hopefully, we don't have any more of those and that is behind us, and we can go on and we can win the championship."
Dario Franchitti and Rubens Barrichello were fourth and fifth-quickest, respectively.
Qualifying for Sunday's 85-lap main event will take place Saturday afternoon at 2:30 pm PT. A pre-qualifying practice will go off earlier that morning at 10:50 am PT.