NFL

Giants corners struggle against Cowboys

LOOK UP, WEBSTER: It was the definition of a defensive breakdown as Giants cornerback Corey Webster loses track of Dez Bryant on a 38-yard completion that led to the Cowboys’ first score in Big Blue’s 24-17 loss last night. (Reuters)

As the summer days of training camp bled into last night’s season opener against the Cowboys, there was much hand-wringing about the Giants’ lack of depth at cornerback.

With each day, it seemed the Giants suffered another injury setback at cornerback.

At least they could count on veteran incumbent Corey Webster, the team’s best, most dependable cornerback the past few years. So they thought.

Last night Webster became the weak link in the secondary, giving up several big plays to the Cowboys receivers in the Giants’ season-opening 24-17 loss.

First, Webster was beaten badly by Dallas receiver Dez Bryant on a 38-yard pass play that nearly went for a touchdown before safety Antrel Rolle made a saving tackle.

Dallas scored two plays later on Tony Romo’s pass to Kevin Ogletree for a 7-3 first-half lead.

It didn’t take long before Webster was torched again. Ogletree left Webster frozen on the right sideline with a rudimentary schoolyard stop-and-go move and easily hauled in a 40-yard Romo scoring pass on the opening possession of the second half.

“Corey’s better than that,’’ Tom Coughlin said. “He just got beat by a go route. I don’t know whether there was a lapse or not, whether he thought they wouldn’t throw the ball down the field. It certainly was a very accurate throw and the receiver got himself in position. Corey will bounce back, though. He’s a fighter.’’

Webster, describing the play, said, “He double-moved me, and me being an aggressive corner, I bit on the double move and he was open over the top. It was nothing special.’’

Except that it gave the Cowboys a 14-3 lead.

Webster later gave up a 20-yard pass play to Miles Austin, leading to the Cowboys’ third touchdown of the night.

His shoddy play was highly alarming for a cornerback corps that has been debilitated by injuries that already claimed Terrell Thomas (out indefinitely with a knee injury), Prince Amukamara (out last night with a high ankle sprain) and rookie Jayron Hosley, who had an impressive training camp but sat out with turf toe.

The Giants began the season last night with Michael Coe, who spent part of last year on injured reserve with a shoulder injury, starting opposite Webster.

Coe, named the starter days ago, outperformed Webster — until he left the game at the start of the fourth quarter with a hamstring injury suffered one play before he broke up a pass to Ogletree in the end zone.

“I don’t feel like this is a big injury,’’ Coe said, indicating he might not miss any games.

So the troubles continued at corner for the Giants, who replaced Coe with Justin Tryon.

It didn’t take long before Tryon was beaten by Austin, the Garfield, N.J., native, on a 34-yard pass that gave the Cowboys a 24-10 lead with 5:57 remaining in the game.

mark.cannizzaro@nypost.com