But no one believed them ... until last night.
With a dominating defensive performance and an amazing game-winning drive directed by Eli Manning, the fearless Giants shocked the NFL with a 17-14 triumph over the New England Patriots at University of Phoenix Stadium, recording one of the biggest upsets in Super Bowl history and ruining the Patriots' quest for a perfect season.
Manning's 13-yard pass to Plaxico Burress - who predicted victory last week - with 35 seconds left in the game finished a 12-play, 83-yard drive as New York secured its place in history.
In addition to capturing their first Super Bowl in 17 years, the Giants became just the fifth double-digit underdog to win the event. The Patriots, who entered the game 18-0, were favored by 12 points.
"It's the greatest feeling in professional sports," a teary-eyed Burress said. "Nobody gave us a shot."
It took resiliency by the Giants, but that's what defined this team all season.
After an 0-2 start, New York (14-6) became the lowest seed to represent the NFC in the Super Bowl, winning three straight playoff games on the road.
That's why the Giants didn't flinch after the three-time Super Bowl champion Patriots went ahead 14-10 with 2:42 left in the game.
The key play came with 1:15 left and the Giants facing third-and-five at their 44-yard line. Manning dropped back to pass, somehow escaped several Patriots clutching his jersey and heaved a 32-yard pass to David Tyree, who out-jumped Rodney Harrison and came down with the ball at the Patriots' 24-yard line.
Four plays later, Manning lobbed the touchdown pass to Burress, who was wide-open in the end zone. Burress, who had predicted a 23-17 victory, faked a slant pattern that fooled cornerback Ellis Hobbs, then raced for the corner of the end zone. Manning was 9-for-14 for 152 yards and two touchdowns in the fourth quarter, overshadowing the NFL's Most Valuable Player.
Patriots quarterback Tom Brady, who was harassed all game by the Giants' pass rush, missed on two long throws in the final seconds.
New England, which had set the NFL single-season scoring record (36.8 points a game), was held its fewest points in a game this season.
"We had a great season; we just didn't win the game," Brady said. "Tonight doesn't take away from anything we have done over the course of the season."
The Patriots were attempting to become the second team to finish as undefeated Super Bowl champions and the first to accomplish the feat with a 19-0 record.
"We're obviously disappointed," said coach Bill Belichick, who stepped down from the podium after quickly answering seven questions.
The Patriots might have more questions to answer this offseason because of Spygate.
The Boston Herald reported Saturday that, according to a source, a member of the New England's video staff taped the St. Louis Rams' last walkthrough before the 2002 Super Bowl. The Patriots called the allegations "absolutely false."
New England was disciplined earlier this season for videotaping New York Jets defensive coaches as they signaled to players.
The bigger problem for the Patriots last night was the Giants' pass rush.
"I don't know if he got rattled, but he had grass stains," linebacker Antonio Pierce said.
Said New York defensive end Michael Strahan: "You could see they were frustrated and a little bit surprised."
Manning, who has often been criticized for his lack of emotion, surprised many with his cool play in the fourth quarter.
Manning started the fourth quarter with a 45-yard pass to rookie tight end Kevin Boss. He ended that drive with a 5-yard touchdown pass to Tyree, slipping the throw past cornerback Asante Samuel.
Tyree's first touchdown of the season put New York ahead 10-7 with 11:05 left in the fourth quarter.
Still, it appeared the Patriots were going to escape with a Super Bowl victory in the fourth quarter, just as they had done three times earlier in this decade.
Trailing 10-7, Brady marched the Patriots 80 yards in 12 plays and hit a wide-open Randy Moss for a 6-yard touchdown pass. Wide receiver Wes Welker caught three passes on the drive and tied a Super Bowl record with 11 receptions in the game.
But instead of hoisting a fourth Lombardi Trophy, the Patriots had to watch Manning's career-defining drive.
"He is the two-minute king," Strahan said. "When we got the ball, I was begging everyone to repeat that we were going to win because we believe in Eli."
Manning had his chance in the end because Belichick might not have believed in kicker Stephen Gostkowski.
On New England's first drive of the second half, the Patriots decided to go on fourth-and-13 instead of trying a 48-yard field goal. Gostkowski's longest kick this season was 45 yards.
But the decision is being second-guessed after a three-point loss.
Asked if he thought about going for the field goal, Belichick said, "Yeah, but it was a 50-yard field goal."
For once this decade, the Patriots didn't make all the right calls and the game-deciding plays.
The Giants did.
"We shocked the world," Pierce said, "but not ourselves."