DAYTONA BEACH, Fla. -- Even though driving a Daytona Prototype won't help him much in the Daytona 500, Jimmie Johnson was happy to be in a race car -- any race car.

Johnson was behind the wheel of the No. 99 Gainsco Pontiac Riley when a clutch problem forced the car to the pits for repairs in the early stages of the Rolex 24 Hours Grand-Am race at Daytona International Speedway.

Streak ends

David Donohue chased down Juan Montoya just 41 minutes from the finish of the Rolex 24, then held the former IndyCar and Formula One driver off by the race's closest margin.

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After finishing his first shift in the car Saturday night, Johnson said he was grateful for the opportunity to drive, even though replacing the car's shifting fork had cost the team eight laps to the leaders. More than anything, in the absence of NASCAR testing this season, it gave the three-time defending Sprint Cup champion a chance to engage his brain before the 51st running of the Daytona 500 on Feb. 15.

"It's nice," Johnson said after turning the car over to teammate Jimmy Vasser. "It really is nice just to get the racing butterflies going, get out on the track, hear the national anthem. I got goose bumps listening to the national anthem [Saturday]. That was neat.

"It's nice to get your brain going again. Just like this series [Grand-Am], we come down and have our biggest race at the beginning of the year, so this year, mentally, I think it's more important to run this race than it's ever been."

Johnson has been fighting a respiratory infection since returning from a vacation to Tahiti during the offseason.

"I can't get rid of it," Johnson said. "I've been through two rounds of antibiotics. I had a five-day Z-Pak [Zithromax], and then another five-day one that I'm just at the end of. It's like the last bit in my head I can't get rid of."

Despite mechanical problems, Johnson teamed with Vasser, Alex Gurney and Jon Fogarty to finish seventh.

Power deficit thwarts Montoya

Though down on power compared with the winning No. 58 Brumos Porsche Riley driven to the checkered flag by David Donohue, Juan Montoya did a masterful job of keeping his Ganassi Racing Lexus Riley at the front of the field -- until Donohue surged past him with just more than 30 minutes left in the Rolex 24.

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It's a little unfair, but it is what it is. I think second place for this team is still a great thing.

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JUAN MONTOYA

Montoya, who teamed with Memo Rojas and Scott Pruett, held off the No. 59 Brumos Porsche for second place.

"Being realistic, we shouldn't have even been in second place," said Montoya, who has two Rolex 24 victories on his resume. "I have to thank everybody at Chip Ganassi. They've done a tremendous job.

"The annoying thing is we brought a car with less wing than they did. We had less wing, but we had such a good handling car. But you get traffic, and they just blow by you. They get traffic, and you can't even keep up with them. It's a little unfair, but it is what it is. I think second place for this team is still a great thing."

The son of the late Mark Donohue, David Donohue, teamed with Darren Law, Buddy Rice and Antonio Garcia to give Brumos its first victory in the event since 1978.

Mears' perspective has changed

Once upon a time, Casey Mears considered himself an open-wheel driver and a road racer, but six full seasons of Sprint Cup racing have altered his perspective on the Rolex 24 Hours.

"Four years ago, I felt more like a road racer," said Mears, who teamed with Danica Patrick, Rob Finlay and Andy Wallace to overcome an electrical problem and finish eighth in his No. 2 Childress-Howard Motorsports Pontiac Crawford. "Now I feel more like a NASCAR guy coming in for the weekend.

"But it doesn't take long to find your roots."