HOUSTON -- Scott Dixon is larger than expected in Helio Castroneves' rear-view mirror.
Dixon won the first leg of the Shell and Pennzoil Grand Prix of Houston at Reliant Park on Saturday, with Castroneves finishing 18th. Once a 49-point lead for Castroneves, the separation with two races left is just eight points.
Dixon will be favored to win Sunday's second race given that he swept the doubleheader at Toronto in July. Castroneves will have his work cut out for him.
Simona De Silvestro scored a career-best second in the race Saturday. Danica Patrick is the only woman to have won an IndyCar race.
Justin Wilson finished third, Simon Pagenaud was fourth and Josef Newgarden fifth.
Pagenaud remains in the championship hunt; he's only 50 points out of the lead. The most points a driver can earn in a race is 53, which means there are 106 still to be won this season.
Dixon is seeking his third career championship; Castroneves and Pagenaud have not won titles in this series.
Dixon also won his 33rd career race, most among active drivers. He is just one win behind Al Unser Jr. for sixth place all-time.
Castroneves slowed on Lap 23 and brought his car to pit road for attention. The problem was fixed in less than eight minutes, but the Brazilian was still nine laps behind the leaders.
Charlie Kimball and James Hinchcliffe each had problems at the start of the race. Kimball's clutch wouldn't engage on the first standing start, forcing IndyCar to abort it. On the second try, Hinchcliffe seemed to have a clutch problem, and his car stopped after initially moving.
Two cars behind him swerved to miss him, but Ed Carpenter, who started on the last row, could not because his view was temporarily blocked.
"One of the cars I was following (Tristan Vautier) dodged to one side and I tried to dodge to the inside but I clipped Hinch's car," he said.
Carpenter's car swiped the left rear of Hinchcliffe's car, with debris scattering as Carpenter's car spun around.
Neither driver was hurt, but Hinchcliffe was upset, apparently with his team.
"I know what happened; I don't want to talk about what happened," he said on the television broadcast, adding that blame "is all over the place."
Takuma Sato won the pole in an abbreviated morning qualifying session, but it was noteworthy, the first for his team, A.J. Foyt Racing, in the series since 1999 (Billy Boat at Atlanta Motor Speedway). Houston also is Foyt's hometown.
Sato then had trouble in the race, starting with a cut tire during the initial caution. Later, his radio failed and then he hit the tire barrier in Turn 3.