The win gives the Giants their first season sweep of the Cowboys since 2011 but, more importantly, allows them to hang on to their position for a possible wild-card berth, which, if they get it, will be their first trip to the postseason since 2011.
The Cowboys were uncharacteristically sloppy with their ball security, turning over the ball three times -- two interceptions by quarterback Dak Prescott and one lost fumble by receiver Dez Bryant on his first catch of the game, which came late in the fourth quarter.
"He ran a slant. I knew it was coming," said cornerback Janoris Jenkins, who forced Bryant's fumble. "I waited till he took a few steps and swiped at the ball physically. It popped out and we got a turnover."
"When you put pressure on the quarterback, that is what happens," added Giants safety Landon Collins, who recorded six tackles and who recovered Bryant's fumble. "(Prescott) is a great player and knows what he is doing, and when you have a tough defense that is in front of you, then you have to pick and choose where you go with the ball."
The sluggish Giants offense managed to capitalize on one of the Cowboys miscues. The first came shortly after New York got its first points of the game on Robbie Gould's 39-yard field goal to narrow the Cowboys lead to 7-3.
New York's second score came on one of the Cowboys' miscues, when cornerback Leon Hall recorded his first interception as a Giant, picking off Prescott's pass intended for Bryant. The pick was the second of the game for Prescott, the first time in his young career that he's thrown multiple interceptions in a game.
The Giants converted that turnover into Eli Manning's first and only touchdown pass of the game, a 61-yarder to receiver Odell Beckham Jr. It was Manning's 50th touchdown pass against the Cowboys and Beckham's ninth career touchdown catch of 60 or more yards.
What was particularly impressive about Beckham's catch is how he streaked down the field, finding a new gear that seemed to delight his cheering teammates.
"I was jumping up and down screaming when he took it to the house," said Giants linebacker and defensive captain Jonathan Casillas. "I'm a fan of the game and he's one of the most explosive tremendous players I've ever seen in this game. He caught a 7-yard pass and took it 60 yards. I don't know how many people have actually done that -- Randy Moss maybe?"
The Giants sought to increase their lead, but then the offense reverted to its sloppy ways from earlier in the game. With 2nd-and-9 on the Cowboys' 22-yard line, Manning's pass intended for receiver Victor Cruz was picked off by cornerback Anthony Brown to squish the Giants scoring drive.
The Cowboys tried late in the game to take back the lead, but came up short. Prescott finally connected with Bryant, whom the Giants had shut out on seven prior targets in the game. However, Bryant's first reception, a 10-yard gain, was forced loose by Jenkins and the loose ball was scooped up by Collins.
Dallas got on the board first thanks to a 31-yard touchdown pass from Prescott to receiver Terrance Williams, who earlier in the drive got a generous spot on a 3rd-and-8 after it looked like Williams had been stopped a full yard short of the first down.
The Cowboys converted the fourth down by sending running back Ezekiel Elliott to the right side against defensive end Romeo Okwara, starting for Jason Pierre-Paul. After Elliott picked up the first down, Prescott found Williams, who was wide open on a blown coverage for the touchdown.
But in the end, the Giants defense made Prescott look very much like the uncertain rookie who played against them in Week 1. Prescott finished 17 of 37 for 165 yards, one touchdown and the two interceptions, while also taking three sacks, two of those sacks a result of the Giants' outstanding coverage down field.
"They seemed like they were flustered," said Casillas of the Cowboys' demeanor late in the game. "The quarterback was frustrated. ... I feel like we had them where we wanted them at the end of the game."
They did indeed. The Giants held Elliott, who finished with 107 yards on 24 carries, to just four carries for minus-1 yard in the fourth quarter and clamped down even tighter on Prescott, who completed four out of 12 pass attempts for 34 yards in the game's final 15 minutes.
"There's no question that they did a good job with coverage on the back end whether they were playing zone or man," said Cowboys head coach Jason Garrett. "There were some tight throws to be made. At times, we made some of those throws and at others we didn't. At times. we made some of the uncontested catches and at others we didn't. Obviously as we go forward, we have to continue to improve in that area."
Another area the Cowboys will want to improve is third down. A week after being held to one conversion out of nine attempts by the Vikings, the Giants held the Cowboys to just one third-down conversion out of 15 attempts (7 percent), was a season best for the Giants defense and far cry from the 46.1 percent conversion rate the Cowboys brought into this week's game.
"Yeah, that's gotta get cleaned up," said Prescott. "The last two weeks, we haven't been as good on third down as we have the rest of the year so whatever it is -- protection, receivers getting open, me getting the receiver the ball -- that's something we'll go back and look at on film and get it fixed."
The Giants, as they have done all season long, shot themselves in the foot with mistakes. New York managed to drive all the way to the Cowboys' 24-yard line, but Manning was sacked, the ball falling out of his hand. Defensive tackle Cedric Thornton quickly scooped it up, recording the Cowboys' 12th defensive takeaway of the season and their first since October.
Despite their big break, the Cowboys were unable to capitalize as Prescott's third-down pass for Bryant at the Giants' 47-yard line was picked off by Jenkins. That interception was Prescott's first in five games.
Kicker Dan Bailey's 55-yard field-goal attempt from the left hash with two seconds left in the first half hit the crossbar.
The Cowboys (11-2) will now turn their attention to wrapping up home-field advantage throughout the playoffs, starting with next week's home game against Tampa Bay followed by a home game against Detroit and then a road game at Philadelphia.
The Giants (9-4), whose wild-card playoff hopes remain alive, will close out their 2016 home schedule next week against Detroit, followed by two road games at Philadelphia and Washington.
NOTES: Dak Prescott's first touchdown of the game marked his 20th for the season, making him the 14th NFL rookie quarterback to register 20 passing scores and the eighth Cowboys quarterback to pass for at least 20 touchdowns in a single season. ... Rookie Romeo Okwara, who made the Giants' 53-man roster as an undrafted free agent out of Notre Dame, got the start at left defensive end for the Giants, in place of the injured Jason Pierre-Paul. He recorded the Giants' first sack of the game in the second quarter, a sack that was also the first of his career. ... Giants RB Shane Vereen, who made his first appearance since Week 3 after spending the last several weeks on injured reserve with a torn triceps muscle, suffered a concussion in the second quarter and was ruled out of the game. ... Odell Beckham's third-quarter touchdown reception was his 33rd from Eli Manning. That catch pushed Beckham ahead of WR Plaxico Burress as the Giants receiver with the most touchdown catches from Manning.