RICHMOND, Va. -- Here's what you need to know from the Federated Auto Parts 400 at Richmond Raceway on Saturday night, the 26th Monster Energy NASCAR Cup Series race:

WINNER: Kyle Larson took the lead from Martin Truex Jr. on a pit stop after caution flew on Lap 397 for a Derrike Cope crash, pushing the race to a green-white-checkered finish. Larson won in overtime as Truex hit the wall, thanks to contact from Denny Hamlin.

It was Larson's fourth win of the year and his first at Richmond. He led 53 laps. Joey Logano was second, Ryan Newman third, Kurt Busch fourth and Daniel Suarez fifth.

"I was surprised at how good our car was. We weren't as good as the 78 (Truex), but nobody really is," Larson said after the race. "This win is all about them (pit crew). ... Those five bonus points with the win tonight are huge for us."

LAST CHANCE: The Federated Auto Parts 400 marked the final regular-season race and the last opportunity for drivers to clinch a playoff berth. Thirteen drivers had secured playoff spots via wins coming into Saturday's race: Martin Truex Jr., Kyle Busch, Kyle Larson, Jimmie Johnson, Brad Keselowski, Ricky Stenhouse Jr., Kevin Harvick, Ryan Blaney, Denny Hamlin, Kurt Busch, Ryan Newman, Kasey Kahne and Austin Dillon. Winless drivers Chase Elliott, Matt Kenseth and Jamie McMurray occupied the final spots based on points.

DALE JR.: He finished 13th in the regular-season finale and did not make the playoffs. He won't win a NASCAR Cup championship in his final year in the Cup Series.

INEXPLICABLE: Danica Patrick brought out the fifth caution on Lap 255 when she spun out after Austin Dillon made contact with her rear tire. Then, chaos reigned on the ensuing pit stop when a safety vehicle stopped on the apron near the entrance to pit road, forcing some cars to go outside the commitment line to avoid the ambulance.

Others were not so fortunate, including Matt Kenseth, who slammed into the rear of Clint Bowyer coming down pit road. Kenseth, who was just inside the playoff bubble, suffered possible radiator damage and was forced to bring his car behind the wall. His No. 20 Joe Gibbs Racing crew worked furiously to repair the car, but he was forced to retire from the race with 132 laps remaining. "We were all just kind of coming to pit road and I saw an ambulance sitting there," Kenseth said. "And there was an accordion effect, and I just couldn't get stopped. I don't know why that ambulance was just sitting there."

“Well, I mean I don’t think they should open pit road if there’s an ambulance parked there. It’s a very narrow entry. Pit road speed is pretty fast – 45 miles an hour or something – and, you know, still I shouldn’t have hit the car in front of me, but I can’t say I was expecting to see an ambulance blocking me, so by the time I looked up and saw him parked there and they were stopping in front of me, I tried the best I could to stop and couldn’t.”

STAGE 2: Truex won his 17th stage this season, pulling away on the long green flag run. Kenseth finished second, Erik Jones third, Logano fourth and Brad Keselowski fifth. Larson was sixth, Dale Earnhardt Jr. seventh, Kurt Busch eighth, Newman ninth and Kyle Busch 10th.

STAGE 1: Kyle Busch won the opening stage after taking the lead on a late restart. Larson was second, followed by Clint Bowyer, Kenseth, Truex, Logano, Jones, Kevin Harvick, Elliott and Kurt Busch. Kenseth, who started on the pole, led 89 laps in the stage until losing the lead on pit stops.

QUICK TRIGGER: NASCAR levied a questionable caution flag on Lap 87 as smoke started to come out of Kenseth's No. 20 Toyota. But Kenseth just appeared to lock up his breaks, and he reported no issue over his radio. NASCAR may have been worried about fluid on the race track.

EARLY OUT: Landon Cassill brought out the first caution when his right rear tire went down and he careened into the outside wall between Turns 1 and 2 on Lap 34. Cassill was treated and released from the infield care center.