The race went two extra laps past the scheduled 90 laps due to a late caution that saw Chad Finchum hit the wall with five laps to go.
Briscoe overcame a spin earlier in the race as well as a speeding penalty on pit road. He now has four wins and nine overall top-10 finishes in 12 races thus far this season.
“We were really not that good in the beginning, we struggled and didn’t have the speed I really anticipated to have here,” Briscoe told FS1. “I was a little worried, but a lot of good cars got tore up so it made it a little easier to get up through the field.
“Ross is always one of the hardest guys to race against and pass. … We’re halfway to eight (wins, his preseason goal).”
Briscoe is No. 1 in the Xfinity point standings with a three-point lead over Noah Gragson.
Chastain took the lead on the final restart, but Briscoe caught him coming out of Turn 2 and went ahead, never to relinquish the lead the rest of the way. Briscoe adds the win at Pocono to earlier victories at Las Vegas, Darlington and Miami.
But Chastain had some consolation: even though he finished runner-up – for the second straight race – he won the final $100,000 prize in the Xfinity Dash 4 Cash race-within-a-race.
“We did everything right, got the push we needed and cleared him going into (turn) one,” Chastain told FS1. “It’s tough to be upset with second, but I am.
“We’re unloading and are in the top two or three every week. I know how lucky I am but man, it’s the memories we take with us, not the money.”
That means Kaulig Racing drivers A.J. Allmendinger and Chastain the last two weeks — won three of the four Dash 4 Cash $100k prizes. JR Motorsports’ Noah Gragson won the first Dash race.
STAGE 1 WINNER: Austin Cindric
STAGE 2 WINNER: Justin Allgaier
Who had a good race: With his third-place showing, Jeremy Clements earned the second-best finish of his Xfinity career. He earned his sole Xfinity win in 2017 at Road America.
Who had a bad race: Several drivers were involved in Stage 1 incidents that knocked them out of the race including Brandon Jones (who won the Truck Series race earlier in the day), Josh Williams, Joe Graf Jr. and Harrison Burton. Brandon Brown also fell out early due to mechanical issues.
Notable: The race had a record nine cautions for 31 laps under yellow. … Austin Cindric looked like he had the dominant car but was involved in a wreck on Lap 53 that knocked him out of the race. Others involved included Justin Allgaier, Ryan Sieg, Myatt Snider, Noah Gragson and Daniel Hemric. … There were no issues in post-race inspection. All cars passed.
What’s next: Pennzoil 150 at the Brickyard, Indianapolis Motor Speedway, Saturday July 4 at 3 p.m. ET on NBC.