BJ Penn and Diego Sanchez will both celebrate birthdays this month, but only one can celebrate a championship victory on Saturday.

Penn will defend his UFC lightweight world championship against Sanchez on Saturday in Tennessee. The bout will be the main event of the UFC 107 mixed martial arts card at the FedEx Forum in Memphis.

Hilo's Penn is 14-5-1, including 11-1-1 as a lightweight (155 pounds) fighter. His only loss as a lightweight came in 2002.

Sanchez, who is from New Mexico but trains out of California, is 21-2. He was once a welterweight title contender, but dropped to the lightweight division this year.

"We know Diego's a great athlete," Penn said during a UFC teleconference yesterday. "He's no pushover. He's going to be out there, pushing the pace and you have to be ready for something like that."

In what Sanchez describes as "a classical mixed martial arts fight," it will feature a clash of styles.

Both are considered well-rounded fighters, although Penn is most renowned for his impeccable jiu-jitsu and methodical submission maneuvers. Sanchez is best known for his aggression and wrestling takedowns.

In preparation for Sanchez, Penn has been training in Southern California for the past eight weeks under the guidance of Marv Marinovich. Penn used the same camp setup prior to his last bout — a fourth-round submission victory over Kenny Florian.

"I guess what I did the same was come to California and work with the Marinoviches and have good sparring partners," said Penn, who will turn 31 on Sunday. "But every fighter you have to prepare for their tendencies.

"I think Diego is good in all areas. He's got great takedowns, he's got great jiu-jitsu ... and he's improved his striking a lot. With all that said, I think his greatest strength is his tenacity."

Because of that, Penn said he "amped up" his cardiovascular training in preparation for Sanchez.

"That's an area we did a lot of work on, people trying to push the pace on us," Penn said. "We amped up our cardio to get ready for what's going to take place on Dec. 12 ... it makes no sense to train with a slow jiu-jitsu guy if you're fighting a strong wrestler who's exploding all the time."

Sanchez, meanwhile, said preparing for Penn was difficult because it was hard to emulate such high level jiu-jitsu.

"Always number one is his flexibility," Sanchez said of Penn. "That's something you really can't prepare for unless you find good flexible jiu-jitsu guys ... I would say there's no one out there with his level of jiu-jitsu and his level of striking."

Another Penn advantage will be experience in main events.

Saturday will be Penn's eighth UFC world championship bout. In contrast, Sanchez is fighting for his first UFC world title.

"There's going to be pressure in every fight," said Sanchez, who will turn 28 on Dec. 31. "There was pressure on me when I won a (wrestling) state championship in high school. If you don't know how to deal with pressure, you're never going to be a champion."

And Sanchez is not exactly a stranger to the spotlight. He burst on to the scene in 2005 when he became the first champion of The Ultimate Fighter reality television series.

Because Saturday will be Sanchez's first championship bout, it will also be his first bout scheduled for five 5-minute rounds (non-title bouts are three 5-minute rounds). He said it will not make a difference.

"I never got tired in one fight in my whole life," he said.

Penn has been training with fellow Hilo fighter Shane Nelson in California. Nelson is scheduled to face Matt Wiman in an undercard bout Saturday.

"We share training partners," Penn said. "Plus, Shane is a southpaw (like Sanchez), so I can shadow him around and move with him."