Ambrose, who is in his fourth year as driver of the No. 9 Ford for Richard Petty Motorsports in Sprint Cup, is considered one of the best "road-course ringers" in NASCAR. The 37-year-old Australian has two career wins in NASCAR's premier series, and both of those victories occurred at Watkins Glen (2011 and '12). In last year's race there, he started on the pole and led the most laps with 51 but was involved in an accident in the closing laps, which led to a 31st-place finish.
Ambrose has yet to win a Sprint Cup race at Sonoma but has come close here in the past. He has finished no worse than eighth in the previous five events at this 1.99-mile, 12-turn course. In the 2010 race at Sonoma, Ambrose held the lead during a caution with just seven laps to go but slowed on the track and fell from his leading position to seventh after he turned his engine off in an effort to conserve fuel. That allowed Jimmie Johnson to grab the top spot. Johnson won at this track for the first time, while Ambrose ended up finishing sixth.
Currently 23rd in the point standings, Ambrose would be virtually guaranteed a berth in the Chase if he wins at Sonoma or any other track during the 26-race regular season. He has yet to make the Chase since becoming a full-time Sprint Cup competitor in 2009.
"We know that the two road races are our best chance to win a race this year," Ambrose said. "That will automatically lock us into the Chase. Clearly, there's a lot to race for at these two tracks for us.
"We've put a lot of energy and effort into Sonoma. We went out there and did the Goodyear tire test earlier in the season. We've done some road-course testing as well, so we feel we're as ready as we can be."
Ambrose has been a road-course expert throughout his racing career. He is a two-time Australian V8 Supercar champion (2003-04), winning 27 races. Ambrose won three consecutive Nationwide events at Watkins Glen from 2008-10 and had a victory in that series at Montreal's Circuit Gilles Villeneuve in 2011.
"My natural skill set obviously is road racing," he said. "I'm quite confident on the ovals but haven't had the same success I've had on the road courses. Really, it's just the years of training. It's my niche.
"I feel very comfortable road racing. I feel like I can apply myself well on the weekend. The biggest thing I try to do on a buildup to a weekend like this, there's pressure building, there's a chance to lock yourself into the Chase, which would make your season. You get a chance to win a Sprint Cup race, which you don't get to do very often."
There have been nine different winners in the past nine Sprint Cup races at Sonoma -- Tony Stewart (2005), Jeff Gordon (2006), Juan Pablo Montoya (2007), Kyle Busch (2008), Kasey Kahne (2009), Johnson (2010), Kurt Busch (2011), Clint Bowyer (2012) and Martin Truex Jr. (2013). Kahne drove the No. 9 car for Petty's team when he won here. He is now behind the wheel of the No. 5 car for Hendrick Motorsports.
Ambrose is hoping he'll be number-10 at Sonoma. It would make him the 11th different driver to win a race this season.
Richard Petty Motorsports competed in the Chase for the first time with Kahne in '09. Can Ambrose give RPM its second berth in the playoffs?
"It certainly would make our year," he said. "We know our year is not complete if you can't make the Chase. It's like you haven't qualified for the finals. I haven't made it to the Chase yet. This format will give us our best chance to do it, if we can win a race at either Watkins Glen or Sonoma. We know that. It would really make our year, no doubt about that. It would certainly make our sponsors and Richard Petty very happy."
A driver from Hendrick has won the last five points-paying races. Gordon started the streak last month at Kansas. Johnson has scored three victories in the past four events (Charlotte, Dover and Michigan). Dale Earnhardt Jr. took the checkered flag at Pocono.
Gordon holds the record for most wins at Sonoma with five, including three in a row from 1998-2000.
Forty-three teams are on the entry list for the Toyota/Save Mart 350.
Series: NASCAR Sprint Cup. Date: Sunday, June 22. Race: Toyota/Save Mart 350. Site: Sonoma Raceway. Track: 1.99-mile, 12-turn road course. Start time: 3 p.m. ET. Laps: 110. Miles: 218.9. 2013 Winner: Martin Truex Jr. Television: TNT. Radio: Performance Racing Network (PRN)/SIRIUS NASCAR Radio.