With two Super Bowl victories in the past five seasons, though, they have emerged as the NFL's top coaching-quarterback tandem.
And the best may be yet to come.
The bond between Coughlin and Manning is there for all to see. It is found in the word, team.
"He epitomizes everything that I believe in as a player," Coughlin said of Manning at a news conference Monday. "(That's) In terms of the quality, the way he produces, the way he handles it among his teammates, on and off the field."
It's sometimes hard to tell whether Coughin has rubbed off on Manning, or vice versa.
Either way, Coughlin and Manning are the perfect match in a state that once had an advertising slogan of "New Jersey and you, perfect together."
"He is confident," Coughlin said of Manning. "He is not arrogant. He has always thought about team first. He is the perfect guy in regard to that because he is continuously spreading things around. He hands the praise out, he distributes it well. He looks to his teammates. He is a guy who is an outstanding leader. He has taken responsibility for his team."
Never was that leadership more evident than late in games this season. Seven times Manning led the Giants (13-7) to fourth-quarter victories and the last was the most impressive - an 88-yard title-winning drive that he started with a pinpoint 38-yard pass.
"A championship is a championship," said Manning, who threw for a career-best and franchise-best 4,933 yards this season. "Each one is special. Each one has special moments during the season and, obviously, different teammates. This year, I am just happy for a number of guys getting a championship.
"...To give them that opportunity for these next five or six months, we can say, `Hey, we are the best. We are the champs.' That's a pretty nice feeling."
The one thing Manning didn't want to hear anything about was having bragging rights over his brother, Peyton, with two championships.
"This isn't about bragging rights," Eli said. "This is a lot bigger. This is about a team, an organization being named world champions, and that was the ultimate goal. That's the only thing that's important, is the team finding a way to get a victory. That's the only thing I care about and Peyton and I both know that's what the goal is every year. It's not about anything else."
"The more his back is against the wall, the better he performs," Mara said before the team left its hotel for a flight to New Jersey and a planned parade up the "Canyon of Heroes" in Manhattan on Tuesday. "There is nobody I would rather have with the ball in his hands at the end of the game, with a chance to win, than Eli Manning."
Linebacker Mathias Kiwanuka said Manning is the perfect quarterback for the New York metropolitan area because he is so resilient on and off the field. He gets knocked down, he gets back up. He gets criticized by the media, he doesn't care.
"If you can't get back up, you are not going to stay around that long," Kiwanuka said.
Coughlin left little doubt that he wants to go for a third title next season, joking he was only 45.
"I mean, it's what I do," Coughlin said at the news conference where Manning was presented another automobile for winning his second Super Bowl MVP award. "So, the alternative I've never really given it a whole lot of consideration. (Just coach) as long as I can."
It's obvious he still wants to coach.
"I don't fish, I don't golf," he said. "My wife keeps telling me, `You better have something to do, buddy boy. If you think you're going to hang around here, you're crazy."'
Mara said it's safe to say the team wants Coughlin to return.
"He might be 65, but he's got the energy of somebody quite younger than that," he said.
Few of the Giants appeared as if they had any energy on Monday morning after a night of celebrating.
Kiwanuka was still wearing a blue wrist band that admitted players to a team party after the game. He like many teammates didn't get much sleep.
However, he saved some of his confidence for next season.
"We won it this year, so there is no doubt in my mind we can," Kiwanuka said of a repeat.
With Coughlin and Manning at the helm, it's certainly possible.