updated 2:06 a.m. ET Nov. 7, 2009

EAST RUTHERFORD, N.J. - Having been to the playoffs the past four years, the New York Giants have rarely referred to a game as must-win unless it was in the postseason.

Things have changed dramatically with three straight losses, and more than one Giant is putting Sunday’s game with the San Diego Chargers into the better-not-lose category.

Forget that the contest will mark the first time Eli Manning and Philip Rivers face each other since the draft-day trade in which the Giants obtained the No. 1 overall pick from the Chargers for the rights to Rivers, who was the No. 4 pick, and three other draft choices, including one which turned out to be linebacker Shawne Merriman.

Middle linebacker Antonio Pierce went so far as to proclaim this another Super Bowl for the Giants (5-3), who have fallen behind Philadelphia and Dallas in the NFC East.

It’s just as important for the Chargers (4-3), who trail the Denver Broncos by two games in the AFC West.

“I don’t ever remember losing three games in a row,” Giants running back Brandon Jacobs said. “So a lot of guys around here realize that in five years they have never really been part of losing three games in a row and we have to do something about it. And a lot of guys are willing to step up and go out and make plays.”

Actually, the Giants lost four in a row in 2006, when they managed to make the playoffs despite an 8-8 record.

The Chargers are very similar to the Giants in that most of their wins have been against the NFL’s weaker teams (Kansas City, Oakland twice and Miami), while their losses have been to Denver, Pittsburgh and Baltimore.

“It’ll be a heck of a challenge,” said running back LaDainian Tomlinson, who scored three touchdowns when the Drew Brees-led Chargers beat Manning and the Giants in their last meeting in 2005.

“These guys are Super Bowl champs from a couple years ago. I think it’s a different type of team,” Tomlinson said. “This is a team that can run the ball effectively, they can throw the ball. Defensive-wise, they get after the quarterback. They can stop the run. And playing at their house, losing three straight, it’s going to be a tough game.”

The key might be the big play. The Chargers have 18 passing plays of 25 yards or more this season, tied for the third in the NFL. The Giants, who have given up at least 40 points in two of their three losses, have surrendered 15 pass plays of 20 yards or more in their losing streak.

“I think everybody in the building recognizes where we are and how we need to respond,” Giants defensive coordinator Bill Sheridan said.

The fun part of the game will be watching Manning and Rivers, who have both become outstanding quarterbacks. The difference is Manning led the Giants to a Super Bowl win over New England in 2008. Coincidentally, the Patriots beat Rivers and the Chargers in the AFC title game to earn the trip to Arizona.

Manning, who has thrown six interceptions in the losing streak, downplayed the head-to-head matchup with Rivers.

“This is the Giants versus San Diego,” Manning said. “It is about us getting back on track and getting that winning feeling again. I think that is my only concern. I think that is kind of in the past.”

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