GLENDALE, Ariz. — A stunning effort from the Giants’ defense and a heroic fourth quarter from Eli Manning brought the New England Patriots’ quest for perfection to a shocking end at Super Bowl XLII, as one of the great teams the sport has ever seen was held in check in the best Super Bowl ever played.

The Giants’ 17–14 win was also one of the great upsets in football history, but to define these Giants by their status as the Davids who slew the Goliath Patriots would be to sell them short. The Giants became a good team the night they gave the Patriots their toughest test in the final game of New England’s 16–0 regular season, and they became a great team when they defeated the Patriots in the Super Bowl.

The Patriots are a great team, too, but they will forever be remembered less for their greatness than for their status as a team that has fallen short of perfection. These Patriots aren’t satisfied with an 18–1 record, and the 1972 Miami Dolphins are still the only undefeated, untied champions in NFL history.

Tom Coughlin deserves the praise he will receive for out-coaching New England’s Bill Belichick, and the game’s Most Valuable Player was Eli Manning. But neither Coughlin nor Manning was as important as Giants defensive coordinator Steve Spagnuolo, who unveiled the perfect game plan, managing to apply constant pressure to Tom Brady while also holding the Patriots’ running game in check. The Patriots scored a touchdown on their first possession and then did it again with less than three minutes left, but holding this great Patriots offense to a mere 14 points is an incredible defensive performance.

For Spagnuolo’s game plan, the key was creating matchup advantages with his pass rush. Defensive end Justin Tuck lined up at defensive tackle and used his quickness to take advantage of the slower Patriots’ guards, and the result was two sacks and a forced fumble in the first half. Linebacker Kawika Mitchell also had a sack in the first half, blitzing Brady up the middle to drop him for a loss of seven yards. Brady rarely had enough time to let his receivers get open downfield, and Randy Moss didn’t catch his first pass until the last 30 seconds of the first half.

Still, it wasn’t easy. Moss caught a touchdown pass from Brady late in the fourth quarter, and it looked as though Brady would be, as he almost always is, the hero on the game’s biggest stage.

But he wasn’t. He was outplayed by Manning, who put together a brilliant performance, the type of performance that makes a player into a legend, the kind of performance that his big brother Peyton made in the Super Bowl a year ago. Whether it’s right or wrong, quarterbacks are judged on the way they play in the biggest games, and Manning’s output both in the Super Bowl and in the three playoff games that got the Giants to Glendale has transformed him in just a few weeks from a scapegoat to a superstar.

The reputation of Brady, on the other hand, will take a hit. He fell short of joining Terry Bradshaw of the Pittsburgh Steelers and Joe Montana of the San Francisco 49ers as the only quarterbacks with four Super Bowl rings, instead becoming 3–1 as a Super Bowl starter.

And the hit Belichick’s reputation took was even greater. Not only did he get out-coached by Coughlin, the man who began his season as a lame duck on the verge of getting fired, but he endured in the run-up to the game new questions about his methods.

Just as this season started with a Patriots employee getting caught taping the Jets’ defensive signals during the first game of the season, resulting in severe sanctions for Belichick and the Patriots, it ends with reports that the day before the Patriots won their first Super Bowl, in 2002, they taped the St. Louis Rams’ final walk-through practice. The Patriots deny the allegations; the league will likely launch another investigation and Senator Specter has said that a Congressional investigation may be warranted. Belichick ended the game by heading toward the locker room while a second remained on the scoreboard, cementing his status in the minds of many fans as the NFL’s biggest villain.

For the Giants, several unlikely heroes joined Spagnuolo, Coughlin, and Manning as the stars of the day. Jay Alford, a rookie who hardly plays defense and earned a spot on the Giants’ roster mostly because he can long snap, sacked Brady with 19 seconds left and effectively ended New England’s last-ditch effort. David Tyree, a wide receiver who is mostly on the roster to play special teams, caught just four passes for 35 yards and no touchdowns in the regular season, but he had three catches for 43 yards and a touchdown in the Super Bowl. Kevin Boss, a little-known rookie who was forced into the starting lineup when Jeremy Shockey broke his leg in December, started the fourth quarter with a tremendous catch and run, grabbing a Manning pass and out-running Rodney Harrison for a gain of 45 yards.

Giants owner Steve Tisch said after the game that it was the greatest win in the history of the Giants’ franchise, and that was no overstatement. Ultimately, the greatness of the Super Bowl lies in the memories it produces, and the greatest memory for Giants fans will be the greatest play Manning has ever made: A stunning play on which he dropped back to pass, was grabbed and nearly sacked, somehow got free and lofted a ball deep downfield that Tyree jumped for to pluck out of the air for 32 yards with just 59 seconds remaining.

Four plays later Plaxico Burress ran a fade route to the end zone, and Manning hit him with a 13-yard touchdown pass to give the Giants the winning margin. It was the last big play of a big season for Burress, who has toughed it out through an ankle injury all year, suffered with a knee injury last week, and still has been the Giants’ most reliable offensive player.

“We believed in ourselves all year,” Manning said at midfield as he was handed the MVP award. Few outside the Giants’ locker room believed in this team, but on Super Bowl Sunday the Giants proved the world wrong.

Mr. Smith is a writer for FootballOutsiders.com.