The two drivers remained neck-and-neck for the final two laps with Harvick holding on to a late lead to grab his ninth win this season.
William Byron, Cole Custer, Matt DiBenedetto and Ryan Blaney were each eliminated from the playoff field after the race as the postseason moves onto the Round of 12.
Bristol Motor Speedway Results
1. Kevin Harvick
2. Kyle Busch
3. Erik Jones
4. Tyler Reddick
5. Aric Almirola
6. Clint Bowyer
7. Chase Elliott
8. Chris Buescher
9. Ryan Preece
10. Michael McDowell
Full results via NASCAR.com
Busch has yet to take a checkered flag this year, but that hasn't stopped him from remaining one of the most competitive drivers on any given track. The driver of the No. 18 car led 159 laps, won Stage 2 and nearly took down Harvick on the final lap.
Instead, he remains the only driver left in the playoff field without a victory this season.
Joey Logano won Stage 1 to clinch a spot in the Round of 12.
Joining Logano, Harvick and Busch in the next playoff round is Denny Hamlin, Brad Keselowski, Martin Truex Jr., Austin Dillon, Chase Elliott, Alex Bowman, Aric Almirola, Clint Bowyer and Kurt Busch.
Dillon advanced after finishing 12th on Saturday despite winning one race this year.
William Byron was close to advancing into the next stage of the postseason until he took on too much damage to overcome late in Stage 2. Byron was three points back of the cutline before he collided with Christopher Bell on Lap 232.
"Yeah, I think it's been a great season," Byron told NBC Sports (h/t NASCAR.com). "I think that we've performed well. I think we would have liked to perform better, based on how we ended last year. But we got a win and I feel like really the last five or six weeks, we've had all top-10 runs, besides Richmond, which is our worst track. I don't know—hopefully continue being fast the next few weeks."