Exiting off Turn 4 on the final lap overtime, Dillon got a big push from Kevin Harvick and then cut to the inside of Wallace, nudged him briefly and cleared him in time to take the checkered flag Thursday night at Daytona International Speedway.
The qualifying race win by Dillon is the first for Richard Childress Racing since 2000, when the late Dale Earnhardt won last of a record 10 in a row.
“I was talking to my spotter before the restart and I said we had (Harvick) behind us and he’s been pushing well all night but he had (Ryan Blaney) and I knew the manufacturer thing would be tough,” Dillon said.
“I made a decent block on the backstretch and then a heck of a push (from Harvick) through (Turns) 3 and 4. I knew Bubba was going to try to block it but I just whipped the wheel and it worked out well.”
Harvick ended up third, Kyle Busch was fourth and Chase Elliott rounded out the top five.
With David Ragan the top finishing non-charter team in the race, the final spot for open teams in the Daytona 500 starting lineup went to Kaz Grala based on his qualifying speed from Wednesday night.
Byron, by posting the second-fastest speed in qualifying on Wednesday, started on the pole but Wallace quickly moved into the lead on Lap 1.
Byron with a shove from Dillon reclaimed the lead on Lap 2.
After 10 laps, Byron remained out front followed by Dillon, Harvick and Elliott.
At the start of Lap 13, Harvick moved into the lead with a shove from Blaney, who moved into the second spot.
With a shove from Byron, Wallace got out ahead of Harvick and in the lead again on Lap 17.
Wallace got hung out in the middle and Harvick reclaimed the lead on Lap 19. Dillon helped Byron get back out front of the pack on Lap 20.
After 30 laps, Byron continued to dominate the race with Dillon close behind. Blaney ran third and Brad Keselowski fourth.
Dillon got around Byron to grab the lead for the first time on Lap 34. Harvick quickly reclaimed the lead on the following lap.
On Lap 36, Chase Briscoe spun exiting off Turn 2, which triggered a multi-car wreck that also collected Grala, Garrett Smithley and Anthony Alfredo. It was the first caution for an on-track incident in either Duel.
All the lead-lap cars pit for fuel and tires with Blaney the first off pit road.
On the restart on Lap 41, Blaney was followed by Harvick, Byron and Dillon.
Using the high line, Byron, with a push from Dillon, moved back into the lead on Lap 43.
With 10 laps remaining, Byron continued to lead the way while Noah Gragson was the top running non-charter team in the race.
At the start of Lap 53, Martin Truex Jr. took over the top spot for the first time in the race as Byron dropped to second.
Harvick went to the inside of Truex and came away with the lead with six laps remaining.
Entering Turn 1 on Lap 57, Smithley got into Keselowski and triggered a multi-car accident that also collected Ross Chastain, Gragson and Byron, who had significant damage to the rear of his No. 24 Chevrolet.
The incident sent the race into overtime, where Truex led the way followed by Wallace, Kyle Busch, Dillon and Kurt Busch.