HOUSTON (Saturday, Oct. 5, 2013) -- Scott Dixon won for the fourth time - the third on a street circuit - in Race 1 of the Shell and Pennzoil Grand Prix of Houston to slice Helio Castroneves' championship points lead from 49 to eight heading into the penultimate race of the IZOD IndyCar Series season.

The second 90-lap race on the 1.683-mile, 10-turn course is at 1 p.m. (ET) Oct. 6. The final race Oct. 19 at the 2-mile Auto Club Speedway oval in Fontana, Calif., will mark the eighth consecutive year that the series title has been decided in the finale.

Castroneves started a season-low 21st and finished 18th in the No. 3 Shell Pennzoil Team Penske car. He developed a shifter issue early in the race and dropped nine laps behind during repairs on pit lane. He had been the only driver to complete all 2,003 laps entering the race.

Dixon has an average finish of 2.2 through five of the six races that constitute doubleheaders and 7.1 on street circuits. He can earn another SONAX Perfect Finish Award, adding $50,000 to the $100,000 he earned by sweeping the races at Exhibition Place in Toronto in July, with a victory in Race 2. Dixon's next victory will tie Al Unser Jr. for sixth on the all-time Indy car list with 34.

Dixon, who started third, pitted on Lap 64 just before a full-course caution for the stopped car of Oriol Servia. Will Power in the No. 12 Verizon Team Penske car regained the point on the exchange, but he had to pit for the final time on Lap 73, which put Dixon back at the front of the field for the duration. He won under caution.

Simona De Silvestro finished a career-high second and Justin Wilson earned his fourth podium finish of the season.

Also on Oct. 5, Sage Karam held off Schmidt Peterson with Curb-Agajanian teammate Gabby Chaves to win the Firestone Indy Lights Grand Prix of Houston.

Karam's first road/street circuit victory, while three of the four fellow title contenders faltered in the penultimate race of the season, set up a winner-take-all scenario with Chaves at Auto Club Speedway on Oct. 19. Karam leads by 16 points.

Karam, who started from the pole in the No. 8 Schmidt Peterson with Curb Agajanian after the lineup was set by entrant points, led every lap in the timed race on the 1.683-mile, 10-turn course.

Carlos Munoz, who entered the race two points behind Karam, finished a season-low 12th and was eliminated from title contention. So was Jack Hawksworth, who was 11 points behind but finished sixth. Peter Dempsey also was eliminated.

INDYCAR