Will Power is aiming to use his milestone 100th IndyCar start in Sonoma this weekend to take him another step closer to this year’s championship.

The Australian heads to one of his favourite venues with a slender five-point lead over American Ryan Hunter-Reay in what is one of the closest championship races in years for the title.

Teammate Helio Castroneves and New Zealand’s Scott Dixon are all within 30 points of the lead and even fifth placed Canadian James Hinchcliffe is just 63 behind.

“It’s insanely competitive,” said Power, who regained the points lead with a runner-up finish at Mid-Ohio on August 5.

“You haven’t seen anyone consistently win poles or win races. No one dominates this series.

“It just proves how tough it is and tight it is. You have to work on all the finer points of your driving just to be competitive.

“Anyone in any other series in the world could come here and I can guarantee you it would take them a good year to get competitive, if they are a good driver.”

Power heads to Sonoma with every reason to be confident of extending his championship lead.

He’s the only two-time IndyCar winner at the Californian circuit, taking the race from pole position in the past two years.

And his confidence was only enhanced following testing at the 3.1 mile (4.99km), 12-turn road course earlier this month.

“This new car is really quick around here,” said Power, who is close to claiming the Mario Andretti Trophy for most road course points for the third straight year.

“I think it’s going to be good racing. Everywhere we’ve been where we’ve expected little passing, there’s been a lot.

“I think there’s going to be good racing here. Fans are in for a treat.”

The Sonoma Grand Prix begins with practice and qualifying on Friday and Saturday before the 85-lap race starts at 1.35pm on Sunday (0630 Monday AEST).