UFC heavyweight champion Brock Lesnar had a message for his opponent, interim heavyweight champion Frank Mir.

"I'll be seeing you in the octagon on Saturday night," Lesnar said during a pre-fight news conference from Mandalay Bay's House of Blues. "I hope you're prepared."

The two mixed martial arts fighters will square off Saturday night in Las Vegas in UFC 100 to determine who is the ultimate heavyweight champion.

These opponents are no strangers. They met back in February 2008 -- a fight in which Mir won -- when Lesnar was still fresh on the UFC scene and Mir was still working on a comeback.

Mir, who once seemed unstoppable in the octagon, has been coming back from a serious motorcycle accident he suffered in 2004. People questioned if he'd ever be able to fully recover from the leg injury he suffered, but he silenced his critics last year.

In Dec. 2008, Mir knocked out Antonio Rodrigo 'Minotauro' Nogueira to win back a portion of the heavyweight title.

Almost immediately after the fight, Mir knew who his next opponent would be -- Lesnar.

Since losing to Mir in his first-ever UFC fight, Lesnar rebounded with stellar results in the octagon. He scored a three-round shutout win over contender Heath Herring and then downed legend Randy Couture to win the UFC heavyweight title late last year.

After defeating Couture, Lesnar set his sights on Mir, wanting to avenge his previous loss.

"Nobody likes to lose, and I'm a sore loser, especially when I feel I gave the (first) fight to him," Lesnar said on the UFC Web site.

Lesnar will have his chance to even the score against Mir on Saturday.