New York led 21-3 at the end of the first half, but Jacksonville capitalized on two second-half turnovers to mount the franchise's biggest-ever comeback, ending its own four-game losing streak and extending the Giants' winless streak to seven games.
"We've talked about this and we've talked about turnovers. Two turnovers for touchdowns?" Coughlin said. "We could have knelt on the ball in the second half and had a better chance to win."
The Jaguars earned 258 total yards of offense, 55 of which came on an 11-play drive that ended with a 43-yard field goal to seal the victory will 28 seconds remaining. Jacksonville's game-winning kick ended a second half marred by injuries to two New York right tackles and a fumble by tight end Larry Donnell.
"A very disappointing, discouraging [loss], all of the above for us," Coughlin said. "We came down here feeling like we could win. Thought we prepared well. And nothing happens on game day."
"It's a long game. Sixty minutes. That's is why it's that. You have to play four quarters. We're playing two, maybe three sometimes."
Despite seven catches for 90 yards from Odell Beckham Jr. and two touchdowns and 91 yards on 26 carries from Rashad Jennings, the Giants' loss moved them to 3-9, tied with Washington for last in the NFC East.
Jacksonville improved to 2-10 on the season and will face the Houston Texans at home next week. New York travels to Tennessee to play the Titans on Dec. 7.
- Christopher Woody