Keselowski managed to make it through pit stops despite mechanical problems, then grabbed the lead on a restart with eight laps to go and pulled away to win the NASCAR Nationwide race at Michigan International Speedway on Saturday.
"The clutch issue was something I was really nervous about," said Keselowski, a Michigan native who also won last year's Nationwide race here. "I didn't know if that was going to cost us the race. I tried to be cool about that, but it's easy to get upset."
Edwards finished second, barely edging out a charging Kyle Busch.
Edwards and Keselowski raced side-to-side for a large portion of the race without incident. Both drivers are on probation for a high-profile confrontation at Gateway International Raceway last month.
"It's like both of us are probably thinking the same thing, don't be the guy that messes this up," Edwards said. "But he raced me very cleanly, I thought we raced very well together, and that's the kind of racing that I'm sure both of us want to be doing."
Meanwhile, it was another rough day at the racetrack for Danica Patrick, who went down a lap to the leaders early on and struggled to a 27th-place finish.
Patrick said her car was extremely loose early on -- "I hope I don't crash," she remembered thinking -- but the team got a handle on the car's handling late in the race.
"If we could have started the race the way we finished it, it would have been a very different story," Patrick said. "It's all right. It's all part of it."
Driver Robert Richardson Jr. was transported to a hospital after a crash. A team spokesman said Richardson, who hit his head, had a CAT scan that was negative. He also injured his left leg.
It was the fourth Nationwide victory of the season and 10th of his career for Keselowski, who holds a dominant 347-point lead in the series standings.
Keselowski won despite clutch issues that gave him problems during pit stops -- and during an attempt at a post-race victory burnout.
"It was an issue on the burnout," Keselowski joked. "I think that was the most frustrating part."
Edwards was hoping he could "steal" a victory, but acknowledged the best car won the race.
"Brad was able to just launch out front on that last run," Edwards said. "It was just a battle for second then, and it was a pretty good battle. I had a pretty good time racing there that last lap."
It was the second race for NASCAR's next-generation Nationwide car, which made its debut at Daytona.
"I think it raced well," Edwards said. "I think the safety improvements are good. The only thing I would wish for is just less downforce, more horsepower."
Keselowski said Edwards congratulated him in victory lane and downplayed the rivalry.
"Sometimes, cars just run into each other," Keselowski said. "There was the recipe for the same cake today, and it just didn't get baked."
Keselowski dominated the first half of the race, at one point holding a lead of more than 11 seconds. But his clutch acted up on a pit stop near the race's halfway point, causing him to lose the lead to Menard.
Edwards took the lead on lap 77, with Keselowski on his tail as Menard slipped to third. After some close racing through slower traffic, Keselowski then went back to the lead with 40 laps to go.
Kevin Harvick pitted from third place with 24 laps to go, leaving Keselowski and Edwards in the top two spots before they made their own final stops. Edwards pitted with 22 to go, and Keselowski one lap later.
Still battling clutch problems, Keselowski had trouble getting out of his pits but managed to make it back on the track with only a minimal delay.
Edwards held the lead after the final round of pit stops, as Harvick slid out of contention with a large piece of debris stuck in the front end of his car. He finished 10th.
Meanwhile, Patrick wasn't competitive.
After going a lap down early, Patrick made a green-flag pit stop on lap 32 so her crew could make major suspension adjustments in an attempt to fix the car's handling. Patrick then made a mistake coming off pit road, going above the "blend" line as she re-entered the racetrack, and had to serve a pass-through penalty on pit road.
In six Nationwide series starts this season, Patrick's best finish is 24th at Chicagoland last month.
"They've all had their challenges, but I really felt like we were getting it at the end [of the race]," she said.