NFL

Big Blue ‘D’ must give RG3 harsh introduction to division

Give Robert Griffin III his props. The young rookie has been impressive during his first six games in the NFL. He beat the Saints in the season opener, and since then the Buccaneers and the Vikings.

He has re-energized his team and his city, and looks to be the kind of good kid that will make the NFL proud. But today is the first day of what will define his legacy as a quarterback: playing in the NFC East.

The Giants have said all the right things in leading up to today’s game at MetLife Stadium. They’ve praised Griffin for his poise, his skills and his leadership. But the Giants know playing the Rams and the Bengals and Bucs and the Vikings is not the same as Giants-Redskins. Today they will welcome RG3 into one of football most physical divisions.

“You’re going to play your division rivals tough,” said Giants safety Antrel Rolle, the reigning NFC Defensive Player of the Week. “That’s just the way it goes.”

Griffin is smart enough to know the NFC East will be different than any other football he plays during the regular season. He got a warning when Osi Umenyiora called him “Bob” soon after he was drafted.

“When he does anything in the league, we will call him his name,” Umenyiora said then.

Griffin says he didn’t take offense, and Umenyiora tempered those comments this week. Now says he would call RG3 “Sir Robert Griffin III.” He doesn’t go from Bob to Sir until he can win in the NFC East.

Sonny Jurgensen, Joe Theismann, and Doug Williams became legends because of their play in the NFC East, as did all-time greats like Roger Staubach, Troy Aikman, Phil Simms, Randall Cunningham and Eli Manning. Today, RG3 begins his quest to someday be included in that conversation. These are the most important games of the year.

That’s why a stain mars the Giants 4-2 record like black ink on a white wedding dress. A victory at San Francisco last week might have rekindled talk of being a Super Bowl favorite. But behind the praise and pats on the back is the reality they are winless in their own division.

Losses to the Cowboys and Eagles have the Giants 0-2 in the NFC East. It’s why coach Tom Coughlin isn’t worried about a mental letdown today after last week’s stunning triumph over the 49ers. Being 0-2 in the NFC East is enough said.

“If our expectations are to get anything done we have to get going in the division,” Coughlin said. “And we haven’t played very well against the Redskins.”

Yes, there’s that 0-2 as well — two losses to Washington during last year’s Super Bowl season. The year was at its bleakest when they were beaten 23-10 by the Redskins on Dec. 18, 2011. They had lost five of their last six games and were 7-7.

But then came the “all-in” speech and six straight wins and a new Lombardi trophy for the hallways of the Giants’ training center. There are few things that can give the Giants a bad feeling about last season. Losing twice to the Redskins is one of them.

“This is a team that’s always given us trouble and it’s always a dog fight,” DE Justin Tuck said. “It’s a going to be a game that comes down to the wire and a game where we’re going to have to play our best ball to win.”

The Redskins (3-3) haven’t always commanded much respect with their revolving door of head coaches and quarterback. But now Mike Shanahan has a franchise quarterback in RG3 ,and it points to the dawn of a new era in this ancient rivalry.

RG3 is this era’s Randall Cunningham — the former Eagle whose athleticism, strong arm and smarts made every play a nightmare for Carl Banks, Leonard Marshall and Lawrence Taylor. RG3 has the ability to infuse Giants-Redskins the same way.

Welcome to the NFC East.

george.willis@nypost.com