Tony Stewart wins rain-shortened NASCAR Sprint Cup race at Fontana

The reigning Cup champion claimed the lead from the Joe Gibbs Racing driver on lap 85, after Busch had been up front for most of the running. Once ahead, there was little challenge for Stewart as the race ran caution-free until the expected rain arrived.

When the pits opened during the caution, Stewart seemed to be driving onto pit-road with Denny Hamlin following him, but he then drove back on the track at the last second, while the JGR driver stopped for tyres and fuel, as did a handful of other top contenders.

Although the rain was initially mild, forecasts showed a high chance of it intensifying, making an eventual restart unlikely.

In the end that latter scenario unfolded as cars lined up on pit-road under the red flag, officials then calling the race, to Stewart's joy.

"I've got awesome racecars," said Stewart. "It starts with all of our guys at Stewart-Haas Racing and the Hendrick chassis department. Especially here at California, the Hendrick Engine department really shows up here."

Busch, who led 80 of the 129 laps after passing polesitter Hamlin on lap one, lost some of his early speed following a brush with the wall, finishing second ahead of Dale Earnhardt Jr. His JGR team-mate Hamlin was classified 11th after his stop.

"Trying to run back with Stewart's lap times, that's when I was trying too hard, too close to the fence, got myself in trouble there, caught the right side a little bit," said Busch.

"Overall I'm glad that the rains came when they did, as heavy as they were, we were able to go home with a second-place finish."

Earnhardt, who drove a solid race, also stayed out while his Hendrick Motorsports team-mate Jimmie Johnson pitted ahead of him. The five-time champion emerged in 10th place after his stop and was lucky the race was halted as his car developed a suspected oil leak while running behind the pace car.

Their team-mate Jeff Gordon was a top-five contender as well but had to serve a pit-road penalty under green after motoring from his box while the refueling can was still attached to his car, during his third stop of the day.

Richard Childress Racing's Kevin Harvick finished fourth after enjoying an interesting battle with Stewart early on, as the eventual winner made his way through the field.

Roush Fenway's Carl Edwards seemed to be gaining momentum as the race progressed but was only able to move up to fifth place by the time it rained.

Kurt Busch stayed out during the caution as well and got his first top-10 finish for Phoenix Racing.

Roush's Matt Kenseth finished the race in 13th but was put back to 16th as the last car on the lead lap, due to a pit road penalty caused by an uncontrolled tyre from his crew during his last stop under caution.

Results - 129 laps:

Pos  Driver              Team/Car                         Time/Gap
 1.  Tony Stewart        Stewart-Haas Chevrolet       1h36m39.000s
 2.  Kyle Busch          Gibbs Toyota                     + 3.556s
 3.  Dale Earnhardt Jr   Hendrick Chevrolet               + 5.767s
 4.  Kevin Harvick       Childress Chevrolet              + 6.951s
 5.  Carl Edwards        Roush Fenway Ford                + 9.307s
 6.  Greg Biffle         Roush Fenway Ford                + 9.664s
 7.  Ryan Newman         Stewart-Haas Chevrolet          + 11.001s
 8.  Martin Truex Jr     Waltrip Toyota                  + 11.579s
 9.  Kurt Busch          Phoenix Chevrolet               + 14.285s
10.  Jimmie Johnson      Hendrick Chevrolet              + 14.930s
11.  Denny Hamlin        Gibbs Toyota                    + 15.311s
12.  Mark Martin         Waltrip Toyota                  + 15.713s
13.  Matt Kenseth        Roush Fenway Ford               + 16.302s
14.  Clint Bowyer        Waltrip Toyota                  + 17.412s
15.  Kasey Kahne         Hendrick Chevrolet              + 18.244s
16.  AJ Allmendinger     Penske Dodge                    + 24.558s
17.  Juan Pablo Montoya  Earnhardt-Ganassi Chevrolet       + 1 lap
18.  Brad Keselowski     Penske Dodge                      + 1 lap
19.  Paul Menard         Childress Chevrolet               + 1 lap
20.  Regan Smith         Furniture Row Chevrolet           + 1 lap
21.  Marcos Ambrose      Petty Ford                        + 1 lap
22.  Jeff Burton         Childress Chevrolet               + 1 lap
23.  Casey Mears         Germain Ford                      + 1 lap
24.  Joey Logano         Gibbs Toyota                      + 1 lap
25.  Aric Almirola       Petty Ford                        + 1 lap
26.  Jeff Gordon         Hendrick Chevrolet                + 1 lap
27.  David Reutimann     Baldwin Chevrolet                + 2 laps
28.  Bobby Labonte       JTG Daugherty Toyota             + 2 laps
29.  Travis Kvapil       BK Toyota                        + 2 laps
30.  David Gilliland     Front Row Ford                   + 2 laps
31.  David Ragan         Front Row Ford                   + 2 laps
32.  Jamie McMurray      Earnhardt-Ganassi Chevrolet      + 3 laps
33.  Dave Blaney         Baldwin Chevrolet                + 3 laps
34.  Ken Schrader        FAS Lane Ford                    + 4 laps
35.  JJ Yeley            Robinson-Blakeney Toyota         + 4 laps
36.  Landon Cassill      BK Toyota                        + 5 laps

Did not finish:

     Josh Wise           Front Row Ford                    52 laps
     Michael McDowell    Parsons Ford                      41 laps
     David Stremme       Inception Toyota                  37 laps
     Mike Bliss          Humphrey-Smith Toyota             19 laps
     Scott Riggs         R3 Chevrolet                      18 laps
     Reed Sorenson       Turn One Chevrolet                 7 laps
     Brendan Gaughan     Childress Chevrolet                2 laps