In 2004, Ultimate Fighting Championship set up a fight card called "Super Natural."

It came from Randy "The Natural" Couture's nickname and the Super Bowl, which took place the next day.

On that card, BJ Penn beat long-dominant Matt Hughes to take the UFC welterweight title.

Since then, UFC has kept up the Super Bowl weekend tradition with big fights. This year, Penn returns to Super Bowl Saturday for another bout against Georges St. Pierre (10 p.m. EST, pay-per-view). Officially, the fight is for the welterweight title St. Pierre holds; unofficially, the winner could be called MMA's best pound-for-pound fighter.

"This fight is a Hagler-Hearns, it's a Hagler-Leonard, it's any of Tyson's fights from the '80s," UFC president Dana White says.

After beating Hughes, Penn split from UFC and fought in Japan. He returned in 2006 to face St. Pierre, losing a split decision, though he inflicted plenty of damage in the first round.

Penn still moved on to face Hughes, who had reclaimed the welterweight belt in Penn's absence, because St. Pierre was injured. Hughes won the rematch.

Penn moved down to lightweight, beating Jens Pulver, Joe Stevenson and Sean Sherk. In that win streak, he also earned UFC's lightweight belt, becoming one of only two fighters to win a UFC title in two different weight classes.

Now Penn, who says his training discipline has improved since he last fought at welterweight, can become the only fighter to hold two belts at once.

Penn, a natural at hyping fights with a nasty edge unusual for UFC, has used the "UFC Primetime" series and press events to aim a few words — "quitter" among them — at St. Pierre, a soft-spoken French Canadian who needlessly apologizes for his English after an interview.

"Him and his team constantly say they're going to finish me, they're better than me in every aspect," Penn says. "They're disrespecting my skills, and that's a big mistake, thinking they're going to walk through me."

St. Pierre doesn't take much of the bait. "I never said I was going to walk through BJ Penn. ... It's going to be very hard, it's going to cost me a lot of things. But at the end, I'll be the victor."

Both fighters are ranked among the sport's pound-for-pound best — Sherdog puts St. Pierre second behind Anderson Silva and Penn fourth.

St. Pierre shrugs it off. "Pound-for-pound rankings can change in a minute. When you have a bad night, you can lose a fight. Anything can happen in sport."

St. Pierre had a bad night in April 2007, an upset loss to Matt Serra. Since then, he has won four in a row and avenged his losses to Serra and Hughes.

"We're both at our prime," St. Pierre says. "That's why this fight is very interesting."