The Super Bowl, that vainglorious championship game of American football, is less than a week away, and with this game will come grand estimates of just how many people around the world will be watching. American expatriates, European fans of the gridiron game and various curiosity seekers will tune in this Sunday to see the big quarterback duel between Peyton Manning and Drew Brees.

Despite what the NFL would like you to believe, however, the Super Bowl will not be the most-watched club football event of the year. That honor now belongs to the UEFA Champions League Final.

According to a study by Initiative Futures Sports and Entertainment in London, the Champions League Final was the most watched annual sporting event of 2009, bringing in an average worldwide audience of 109 million viewers, compared to 106 million for Super Bowl XLIII. The “total audience” numbers, which represent the number of people who watched at least part of the event, were skewed even more in favor of the Champions League. 206 million watched at least part of Barcelona’s win over Manchester United, while only 162 million saw part of the Pittsburgh Steelers’ victory over the Arizona Cardinals.

So what has made the Champions League Final bigger than “The Big Game(tm)”? One word: Asia.

The study showed that the NFL has a huge domestic audience and has made a few inroads into European television markets, thanks in part to its annual game in Wembley Stadium, but UEFA and its member clubs are well ahead of the NFL in terms of marketing their brands to Asian nations. No doubt, this was helped by the presence of Manchester United, a club that has marketed itself heavily in Asia, in the last two Champions League Finals. Barcelona is also a well-known brand throughout the world, as are many of the clubs participating in the knockout stage this year.

Last year’s Champions League Final also featured Cristiano Ronaldo and Lionel Messi, arguably the two best footballers on the planet. They probably had a bit more pull with international sports fans than Ben Roethlisberger and Kurt Warner.

What’s more, the Super Bowl lacks a really catchy theme song. That never hurts.

Of course, since this is a World Cup year, neither of these games will be the most-watched football event of 2010. Still, the study suggests that both events are growing in stature worldwide, so it will be interesting to see how their audiences will compare as this decade progresses. It will also be interesting to see how well UEFA boss Michel Platini and NFL commissioner Roger Goodell handle their games’ respective financial issues. Goodell has contentious collective bargaining negotiations ahead of him, and they threaten to wipe out the 2011 NFL season. Meanwhile, Platini has to figure out how to deal with the issue of clubs carrying massive debts without undermining the popularity of UEFA’s prize club competition. As huge as these two games have become, neither is too big to fail.