Buescher, who started 26th, dominated along with RFK Racing team-mate and co-owner Brad Keselowski, as the two combined to lead 190 of the 400 laps.
Buescher emerged as the race leader following the final round of green flag pitstops but saw his big lead over Hamlin disappear when a spin by Daniel Suarez brought out a late caution and set up a restart with three laps remaining.
Hamlin initially stayed close to Buescher, but briefly drifted up the track with two laps to go, which allowed Buescher to get away. He held on and claimed his first victory of the 2023 season by 0.549 seconds.
The win – the third of Buescher’s career and second while at RFK Racing – locks him into this year’s 16-driver playoff field with four races remaining in the regular season.
“That was smooth sailing there trying to take care of [my car],” said Buescher. “These guys over at RFK, the #17 team, gave me a great hot rod. It was so good. Just trying to take care of it there.
“Scott [Graves, crew chief] came over the radio, ‘That’s working perfect, keep it up’ and caution. Yeah, that’s about right. I knew even on our green flag stuff we were so strong during the race; I had a good feeling about it there.
“Pretty awesome to pull it off. Proud of everybody. That was a long way from the back [of the field]. Heck of a race for us.”
Erik Jones, LEGACY MOTOR CLUB, Allegiant Chevrolet Camaro and Chris Buescher, RFK Racing, Fastenal Ford Mustang
Photo by: Rusty Jarrett / NKP / Motorsport Images
Despite featuring at the front for most of the race, Keselowski dropped to sixth place at the chequered flag, but banked solid points having also won the Stage 2 of the Richmond race.
Behind Buescher and Hamlin, Kyle Busch ended up third ahead of Joey Logano in fourth and Ryan Preece in fifth.
Just missing out on getting Keselowski at the finish, overall NASCAR Cup points leader Martin Truex Jr. had to settle for seventh, as Aric Almirola secured his best finish since the Martinsville round back in April in eighth.
Austin Dillon and Kevin Harvick rounded out the top 10 at Richmond, while title fighters William Byron and Christopher Bell both struggled for pace and finished off the lead lap in 21st and 20th respectively.
NASCAR Cup Richmond – race results (400 laps)