McMurray broke the modern-day record for fewest starts before his first Winston Cup victory, set last year by Kevin Harvick, who won at Atlanta Motor Speedway in his third start.
McMurray drove the same Dodge that Marlin used to win last year's race at Lowe's Motor Speedway outside Charlotte.
Rain delayed this event three hours, but it could not delay McMurray's impressive drive to victory. The Busch series regular was scheduled to join Chip Ganassi's team next season in the Texaco/Havoline Dodge. But when Marlin suffered a broken vertebra two weeks ago in a crash at Kansas Speedway, Ganassi gave the young driver from Joplin, Mo. an early start.
McMurray finished 0.350 seconds ahead of 2000 Winston Cup champion Bobby Labonte, who was followed by Joe Gibbs' Racing teammate and current points leader Tony Stewart -- both in Pontiacs. Jeff Gordon was fourth in a Chevrolet and Rusty Wallace rounded out the top five in a Ford.
A race that began in mucky, foggy conditions ended under the lights, with the brightest one shining on McMurray.
"I don't believe it," McMurray said. "This is huge. This is a top opportunity here, and Sterling has been great to me. Chip and Felix gave me a great opportunity. Everybody asked me if I'm nervous. I'm very nervous.
"I had a great car in the Busch series on Saturday and learned a lot about the race track. I'm surprised we are here. When we were leading with 150 laps to go, I thought we would finish fifth. I tried to stay focused those last few laps."
McMurray got a call from Marlin from his home in Columbia, Tenn.
"Congratulations, Jamie, that win is way too soon," Marlin said. "I knew Jamie would be a good driver. That same car won Las Vegas and Darlington for us, and Jamie drove the wheels off it today."
Ironically, McMurray was not scheduled to race next week at Martinsville, Va. because of a Busch series conflict.
"They might let me race there next week," he said.
McMurray's victory was universally celebrated, even by the drivers he defeated. Labonte came to victory lane to congratulate Winston Cup's newest winner.
"His little old Dodge is pretty fast and that is what it takes here," Labonte said. "It was a good night for us, but it still wasn't a win."
The third-place finisher remembered racing against McMurray in their early careers.
"When I first met Jamie, we were racing in WKA go-karts," Stewart said. "Man, I'm really happy for him and very happy for the Coors Light team. We're all sad that Sterling had his injury like that and see someone get knocked down in the series, but that is a good pick-me-up for the team."
Stewart has a 97-point lead over Jimmie Johnson atop the Winston Cup standings with five races remaining.
There were five caution flags for 33 laps, with one multi-car collision on lap 231, when Todd Bodine's Ford clipped the tri-oval grass and shot into the side of Ward Burton's Dodge. That started a chain reaction that involved Brett Bodine, Harvick, Jeff Green, Kenny Wallace, Robby Gordon, Ricky Craven, John Andretti and Bobby Hamilton.
None of the drivers was injured.