The game took place back in the day when NFL & AFL were still separate leagues, with the former one's sides being considered superior, even though it was the last game before the merger. The then still AFL side Kansas City Chiefs was squaring up against the heavily-favoured Minnesota Vikings as the 12-points underdog.

Well, the commonly considered inferior Chiefs appeared not only covering the spread but also winnings the title and solidifying its position in the soon unified National Football League. The 12-points underdog Kansas side scored the first 16 points, finishing the game with a humiliating 23-7 score.

Another 12-points underdog story this time during the Super Bowl XLII between New York Giants and New England Patriots. Not only it was another case of a heavy underdog covering against the spread & winning the match, but also of one of the best NFL performances ever! The game was a true rollercoaster. Patriots were leading 14-10 with just under three minutes left in the fourth.

The turning point was when Eli Manning managed to scramble around and avoid the sacking on the third & 5 just to find an open backup receiver, David Tyree. The play was not only a turning point of the Super Bowl Game but also went down in the NFL history books as one of the most remarkable catches. Tyree managed to hold on to the ball by pinning it to the top of his helmet while being tackled. The play helped Giants recover and score a touchdown a couple of plays later stealing the game from the heavily-favoured Patriots. Interesting, but the two sides faced each other once again in the Super Bowl a couple of years later with Giants beating Patriots in a similar fashion, however, as only the 2.5-points underdogs.

It might sound strange, but New England Patriots haven't always been the same Patriots we know nowadays. Back in a day, New Englanders were just unproven upstarts in the league. It was only for the amazing Super Bowl XXXVI performance back in 2001 that Pats became the team we all know nowadays.

Nobody was giving the then struggling Patriots led by the young Tom Brady a chance. As a result, they were heading into the Big Game as one of the biggest underdogs in NFL history. Considering quite a tough season the Pats had that year, bookies priced them up as the 2-touchdown underdogs against the unstoppable St. Louise Rams. After their Super Bowl XXXIV win, the Rams were destined to win another title in the upcoming years. However, when presented the opportunity, things went a bit different direction from what was initially expected. The HoF-packed Rams couldn't handle Patriots' phenomenal defence and only scored 3 points in the first half. On the other hand, Brady and the company got the job done on the offensive end, winning the game by Adam Vinatieri's 48-yard field goal.

This Championship meant everything for the franchise, starting its dominant dynasty, which appeared in the Big Game nine times since then. What is more, the Patriots have not been Super Bowl favourites only once ever since, with the sole exception of Super Bowl XLIX against Seattle Seahawks.

Surprisingly or not, but the biggest spread covered by the Super Bowl underdog is a stunning 18 points and belongs to the then AFL side New York Jets. The upset, that many still cannot get over, served as the starting point of the NFL long-standing success & popularity. Remember the ALF's Chiefs back in Super Bowl IV that we mentioned above? Well, this one was a similar case. The AFL champions had to face one of the strongest NFL's powerhouses Baltimore Colts in the Big Game.

Despite all the media projections & doubts from expects, Jets' Hall of Fame QB Joseph «Broadway Joe» Namath uttered his now infamous guarantee of a win. Luckily, Joe was able to back his hot mouth and outbattled Colts quarterback Johnny Unitas 16-7.

The game finished with a mindblowing upset to the Colts, in which Jets have easily covered the biggest NFL spread of all time. What is more, Jets fans have won millions of dollars beating the bookmakers, which boosted the interest of Super Bowl betting further on.

One more thing before we finish today. Note, the Big Games, in which four of the biggest NFL Super Bowl underdogs won the outright, have gone under the total!