NFL

COLD, HARD SACKS

Sometimes when the rock starts rolling downhill, nothing can be done to prevent the impending avalanche, which is what happened last week when the Eagles piled on an outrageous nine sacks in their 56-21 demolition of the Lions.

It was the second-highest total in Philadelphia franchise history, and it no doubt was fueled by the huge Detroit deficit that necessitated a one-dimensional passing barrage.

“First play of the game they got a sack, so that wasn’t situational,” Giants quarterback Eli Manning said.

Three-game stats aren’t always an accurate barometer, but there’s no doubt the Eagles can get after the quarterback. Thanks to that nine-sack outburst, the Birds lead the NFL in sacks with 14, and defensive end Trent Cole, who amassed 3 ½ sacks last weekend pinning his ears back and charging forward, leads the league with five.

The assignment of keeping Cole under wraps Sunday night when the Giants and Eagles square off at Giants Stadium falls to David Diehl, in his first year playing left tackle. Diehl has been a work in progress but is always steady and his glaring mistakes have been rare. One came Sunday when he was watching for the ball and was late on the snap count amid the crowd noise at FedEx Field, thus unable to impede onrushing Andre Carter from laying a blind-side hit on Manning, causing a fumble the Redskins recovered to gift-wrap their first touchdown.

“Regardless of how it happened, there’s no excuses,” Diehl said. “It affected our team, it affected our drive, we lost the possession. I’m a man, I can stand up and own up to it.”

Diehl allowed one sack to DeMarcus Ware of the Cowboys in the opener.

“You’re playing up against usually their best pass rusher,” Diehl said. “You know what you’re up against, you know they’re looking at you as a new left tackle, they’re looking to test you.”

Coming into this season, Diehl started 66 consecutive games for the Giants but only two as an emergency fill-in left tackle. One of those games was last season’s NFC wild-card playoff loss to the Eagles, in which Diehl played solidly.

“The thing that helps me out for this week is I played the playoff game at left tackle,” Diehl said. “I’ve played up against Trent Cole, I know the type of player he is, at least I have that experience. I feel a lot better this year than I did last year.”

Cole, at 6-3, 270 pounds, is bigger than many of the new-age speed rushers.

“Physical player, a high-motor guy, plays from the start of the snap to the whistle,” Diehl said of Cole. “For a guy his size he’s got great strength and leverage and he really challenges you.”

The upcoming challenge is immense for the entire Giants offensive line, developing into the steadiest unit on the team. For the Eagles, left defensive end Jevon Kearse is not what he once was but remains a big-play threat, and tackles Brodrick Bunkley and Mike Patterson (a pair of former first-round draft picks) are excellent run-stuffers.

The Eagles, under the orchestration of defensive guru Jim Johnson, mentor of new Giants coordinator Steve Spagnuolo, are adept at finding one-on-one matchups up front, making sure they have at least five rushers to prevent double teams anywhere along the line. The Eagles are confident they will win the bulk of the individual battles, as they did in last week’s devastation of Detroit.

“That definitely jumps out at you,” O’Hara said. “We gave up seven sacks to them the first time we played ’em last year and still came out with a ‘W.’ The percentage of winning games giving up that many sacks is probably pretty low. I’m sure Tom [Coughlin] has got a stat for that.”

paul.schwartz@nypost.com