Eli Manning throws an interception that was returned for a...

Eli Manning throws an interception that was returned for a touchdown by the Jaguars after a breakdown on the offensive line.  Credit: Kathleen Malone-Van Dyke

If there’s one thing we’ve learned over the years about Eli Manning, it’s that he will never — ever — criticize his offensive line. Even if it’s warranted.

Manning has played behind lines good enough to win Super Bowls and bad enough to lead to coach firings. It was therefore not surprising that Manning would defend the men up front after a less than perfect — a far less than perfect — game in Sunday’s 20-15 season-opening loss to the Jaguars at MetLife Stadium.

“I thought the offensive line did a good job going against a good front,” Manning said. “That’s why their team has been so successful. Their front four is extremely talented, and they get pressure on the quarterback. I thought [our] guys competed. They hung in there tough. Obviously, that’s football. There’s times where you get some pressure, and you got to make good decisions with it. There’s some times we had great protection, and had a ton of time to really push the ball down the field.”

Manning was under fairly consistent duress against one of the NFL’s best defenses, and while there were some positive moments, there was enough offensive line ineptitude to bear out the concerns heading into the season. The Giants feature an all-new line, with the only holdover — Ereck Flowers — now playing right tackle after flaming out on the left side. They brought in Nate Solder from the Patriots to protect Manning’s blind side, and the interior features rookie guard Will Hernandez, center Jon Halapio and right guard Patrick Omameh.

It was an inauspicious beginning, to be sure. Flowers was penalized on two of the first three offensive plays. He also allowed a seven-yard sack of Manning. In all, the Giants allowed two sacks, six quarterback hits and a tipped pass that was returned for a touchdown in the fourth quarter.

“Again, he had a lot of really good reps and he had a couple he’d like to have back,” Giants coach Pat Shurmur said of Flowers. “He’s going to work to get better, just like every player.”

Flowers, who has been heavily criticized the last three seasons — mostly with good reason — vowed to get better. That may ring hollow, considering all his misplays in recent seasons, but it’s all he’s got.

“It’s cool, I’m just trying to get better,” Flowers said. “The other thing is just try to play more consistent. There were a couple of plays where I just need to, let’s just say more consistent. Let’s just say that. I think I did some good things, but I think there’s some things I need to work on. It’s part of the game.”

Flowers started his first 47 games at left tackle and was clearly overmatched in several games last year. Rather than give up on him completely, first-year general manager Dave Gettleman decided to move Flowers to right tackle.

“It was my first full game at right,” Flowers said. “[Jacksonville had] probably the best rushers yet that I’ve played at right, so it was a little different. But got to get better and move on. Go on to the next game and continue to work at it and get better at it.”

His play will have to get better if the Giants are to make truly meaningful progress after a 3-13 nightmare led to wholesale organizational changes. The Giants are at the Cowboys — who had their own issues on offense in a lackluster 16-8 loss to the Panthers in Carolina — in a Sunday night matchup in Week 2.

“I think we have a lot to improve, and I think that our protection can improve,” Solder said. “I think that was part of the reason that we struggled, and it all starts with balance on everything we do. I think the most important thing you take away from that is where you need to improve, how we need to improve because we know the next team is going to be watching the same film. They’re going to attack us in similar ways and we got to get better at those things.”

Improvement up front is a must. And if it doesn’t happen quickly, then all the preseason optimism will quickly fade into more regular season misery.