The New York Giants were left to rue missed opportunities and a costly late Dexter Lawrence offside as they went down 30-29 to the Washington in Thursday Night Football in Maryland.
Dustin Hopkins successfully converted a 43-yard attempt for the win on the buzzer, although he had missed his initial 48-yard try, only to get a second chance due to Lawrence jumping early.
Washington quarterback Taylor Heinicke, in only his third NFL start, completed 34 of 46 passes for 336 yards, compared to Giants QB Daniel Jones who had 22 from 32 for 249 yards.
Heinicke, who was playing for the injured Ryan Fitzpatrick, claimed his first career win as a starting QB, highlighted by a key fourth-quarter pass for a Ricky Seals-Jones touchdown.
The result earns Washington their first win of the season, while the Giants are 0-2 after their opening defeat to the Denver Broncos.
Jones had put the Giants ahead when he rushed into the end zone in the first quarter, breaking a Kamren Curl tackle.
Washington leveled it up with a Terry McLaurin touchdown from Heinicke's pinpoint throw, after Giants offensive lineman Nick Gates was carted off with a gruesome lower leg fracture. McLaurin had 11 catches and 107 yards for the game.
New York were denied another running Jones touchdown in the second quarter for a tight hold call against CJ Board, eliminating a 58-yard play, before dependable Giants kicker Graham Gano made it 10-7.
Washington grabbed a 14-10 lead at half-time when running back JD McKissic drove down the left for a late touchdown.
Gano reduced the deficit, before Darius Slayton's touchdown from a Jones pass for a 33-yard completion. Hopkins made it 20-17 at the final change with a 49-yard attempt.
The lead changed three times in the final quarter, with Jones pushing the ball downfield, enabling Gano to get within range for a 52-yard attempt, with Hopkins responding with nine minutes to go to make it 23-20.
Slayton fluffed a golden chance to open up a big Giants lead when he got open in the end zone but dropped a Jones pass.
Gano extended New York's lead to six points before Heinicke found McKissic down the sideline for a 56-yard play, the longest of the game. From the next play, Heinicke delivered to tightend Seals-Jones for a catch into the corner to put Washington up 27-26 with 4:33 to play.
Washington gave up a turnover before the Giants earned territory, settling for Gano to convert his 35th consecutive attempt to put them up 29-27 with two minutes to play.
Heinicke and Washington edged forward, with Hopkins' initial attempt with five seconds on the clock missing, before converting his reprieve for the win.