Chris Buescher led the way entering the two-lap overtime – one of six drivers in the top 10 running order still trying to make the playoff in the regular season finale.
With one lap to go, Corey LaJoie gave Blaney a shove that allowed him to clear for the lead. A multi-car wreck erupted when Kurt Busch got into Daniel Suarez in Turn 3 to place the race under caution and secure Blaney’s victory.
“How about that? That was a lot of fun. Gosh, we just barely missed that wreck,” Blaney said. “Got to line up on the front row, got a good push by (LaJoie).
“You never know how the end of these things is going to play out. Down the back (stretch), you don’t know what lane is getting a bigger run. I guess someone got tangled up over there. Hopefully everyone is okay.
“It’s so cool. Win at Daytona, everybody here. Thank you guys for coming. Really special. It’s been a fun two weeks.”
It’s the third win of the 2021 season for Blaney, who won last Sunday’s race at Michigan with a late-race push to the lead by Kyle Busch.
Tyler Reddick, with a damaged car, finished fifth and clinched the 16th and final spot in the playoff field.
Kyle Larson, who finished 20th after getting caught up in that last-lap wreck, still won the regular season title over Denny Hamlin by 18 points.
Buescher had claimed second in the race, but in the post-race inspection his #17 car failed the checks in the early hours of Sunday morning at Daytona as his car was found to have an unapproved track bar mounting assembly.
As a result, the #17 was disqualified from the race, handing Buescher a last-place finish (40th) and he would not get to keep any stage points accumulated in the race.
The disqualification moved Bubba Wallace into a second-place finish, Ryan Newman to third, Ryan Preece fourth and Tyler Reddick gained a fifth-place finish in a wrecked car.
The remainder of the top 10 were Justin Haley, Alex Bowman, Chase Elliott and B.J. McLeod and Josh Bilicki.
In addition to Reddick and Larson, also advancing to the Cup series playoff are: Hamlin, Elliott, Kyle Busch, William Byron, Blaney, Martin Truex Jr, Joey Logano, Kevin Harvick, Brad Keselowski, Bowman, Kurt Busch, Christopher Bell, Michael McDowell and Aric Almirola.
Race results – 165 laps