BROOKLYN, Mich. -- If the Penske entries signaled in qualifying they were the cars to beat at Michigan and for the title, then IndyCar Series leader Sam Hornish Jr.'s car failing after 61 laps of Sunday's Firestone Indy 400 signaled all bets are off.
Helio Castroneves took over the series lead from his Penske teammate by winning the race while defending series champion Dan Wheldon narrowed his gap to the lead from 32 points to 17 by finishing third.
"I told everyone I was going to drive like it was my last race, and we did," Castroneves said. "To leave here with my first victory and to have the championship lead, it's all I could hope for."
Vitor Meira earned the seventh runner-up finish of his career and is now winless in 57 starts.
In a race with the fewest caution flags (2) in IRL history and the third-fastest average speed (193.972 mph), Hornish looked like he might have the car to beat. He took the lead from polesitter Castroneves on the first green-flag lap after three laps were run under yellow while race officials made sure the track was dry after midday storms.
But the first sign of trouble came on Lap 50, when Hornish made an unscheduled pit stop after radioing his crew that his car was running hot. Just 11 laps later, he was out of the race and with an official finish of 19th. That's the same as last.
"The car was handling well and I thought we had a really good chance to win the race," Hornish said. "I'm not really sure what happened, but I know it was an issue with the engine.
"It's a shame to end the day like that, but that's how it goes sometimes."
Sunday's race clarified the title chase in one way. What started as a four-man race for the title was likely trimmed to three when Scott Dixon's car ran out of fuel on Lap 44. While Hornish's uncharacteristic failure left the points race wide open, the mistake by Ganassi Racing in keeping Dixon out too long put the New Zealander out of the hunt and left teammate Wheldon as the only non-Penske entry with a clear shot at the title.
Wheldon, who was also low on fuel at the same time as Dixon, but was allowed to come in under caution for a quick splash, said he was happy to make up ground in the race for the championship.
"It's unfortunate for Sam because he seems to have some bad luck," Wheldon said. "It's always disappointing to see someone go out like that, but at the same time we made up points. I think we got the best out of what we had today."
Castroneves, known for his fence-climbing antics after winning a race, admitted he didn't get very high up on Sunday at Michigan International Speedway.
"After 400 miles, it was a little hard," he said. "The funny thing is it wasn't [the curved fences], it was the banking. That was the first time I went to the Michigan straightaway and the banking is kind of high. After 400 miles, again, I'm like, 'Come on legs, go!' The leg wasn't responding, especially the right one. ... When I grabbed the fence, I was like, 'Whoa, my arms are tired here! What's going on!' Finally I was able to find some cables.
"These are the days I wonder what the heck I'm thinking when I did that."
Conventional wisdom said Hornish needed a good showing at Michigan since there are only two oval tracks left -- Kentucky Speedway and the finale at Chicagoland Speedway -- over the final three IndyCar races. Sandwiched in the middle? Infineon Raceway in Sonoma, Calif., where Hornish has struggled and road-course aces Wheldon and Castroneves have thrived.
"Now we just have to move past this and look ahead to the final three races of the season and try to earn as many points as we can," Hornish said.
At eight points back, Hornish still has more than a fighting chance to win it all, but Sonoma makes his uphill climb look almost as tough as Castroneves' up the fence at MIS.
K. Lee Davis is the motorsports editor at ESPN.com.