Pitted against a New York Giants team heralded for its defense, it was the Cowboys that dominated that side of the football Sunday night at AT&T Stadium.

The Giants gained just 49 total yards in the first half and didn’t cross their own 34-yard line until the third quarter. That drive, a 16-play, 68-yard march downfield stalled inside the red zone and resulted in a field goal.

• Box score: Cowboys 19, Giants 3

A year ago, it was the Giants whose vaunted defense finished No. 2 in the NFL in points allowed and in the top 10 in yardage allowed. The Cowboys were the duct-tape ones that overachieved in finishing just behind their division rival in those rankings.

But at primetime Sunday night, Dallas absolutely smothered the Odell Beckham-less Giants, postings three sacks and an interception. New York totaled just 35 rushing yards in the game.

And what may have been the most exciting defensive play of the game didn’t even count.

With five minutes to play in the second quarter, Sterling Shepard hauled in a short Eli Manning pass in the flat. Sean Lee stopped him before Jaylon Smith drove him to the ground and jarred the ball loose. It wasn’t ruled a fumble, and Cowboys coach Jason Garrett clutched the red challenge flag in his right hand while conversing with a referee before deciding against a challenge.

Smith started at middle linebacker and recorded seven tackles (four solo) in his first “real” game since suffering a career-threatening leg injury in his final collegiate game on Jan. 1, 2016.

After a third quarter that saw a largely lifeless Cowboys offense and with a two-score lead, the defense stepped up again in the fourth quarter. Anthony Brown picked off Eli Manning and gave Dallas the ball with under eight minutes to play.

Ezekiel Elliott and the offense would chew up 5:53 of the remaining time on its ensuing drive.

Extra points

• Jason Witten became the Cowboys’ all-time receiving yards leader on an 11-yard grab in the second quarter. He passed Michael Irvin atop the franchise’s receiving yards list and finished the game with 11,947 career yards.

• The last time the Cowboys gave up just three points in a game was Oct. 20, 2013 against the Eagles.

• Dak Prescott’s 2017 season got off to a rocky start. He overthrew several receivers in the first quarter, including Dez Bryant in the endzone, en route to an 8-of-16 mark with 96 yards and a 68.8 passer rating. In the second quarter, he turned things around, going 9-of-12 for 87 yards, a touchdown and a 122.6 passer rating. After the eight incompletions in the first quarter, Prescott would only throw seven incomplete passes the rest of the game.

• Ezekiel Elliott, who posted just 51 yards in last year’s opener against the Giants, topped that total in the first half. He ran for 104 yards in the game and added a career-high five catches for 36 yards.

• The Cowboys lost Orlando Scandrick in the second quarter with a hand injury.