Faced with a challenge from power players on the professional racquetball tour, Mike Yellen has successfully countered with his mind.

"I can't play that really physical game. I'm not known for my power," said Yellen, the top-ranked player in the world the last three years. "But I can concentrate. The mental aspect of the game is where I draw my strength.

"I just think every shot has a purpose. A lot of guys will try to just blast the ball through you. But I want to hit shots that can beat my opponent more than just physically. I want him guessing."

Yellen is seeded second and will play an undetermined opponent today at 3:30 p.m. in the first round of the Crystal Racquetball Pro-Am at the Crystal Racquet and Health Club in Arlington. Yellen's longtime nemesis -- top-seeded Marty Hogan, who is ranked first in the world -- also will play an undetermined opponent, at 11 a.m.

Along with being the two best racquetball players in the world, Yellen and Hogan have come to epitomize the two prevailing styles of play. Hogan, as close to a legend as the professional circuit can offer, introduced the power game in the mid-1970s and dominated the sport -- until Yellen fought back with intellect.

"Hogan has a lot of natural ability," said Jean Sauser, a touring pro for eight years and now the associate editor of National Racquetball magazine. "But Mike makes up for his lack of natural talent with his head. He is so methodical and is easily the smartest player on the tour."

Yellen, who drew much of his knowledge of the game's nuances from squash, picked up racquetball at age 13 and was a professional three years later. Now, at 25, he has a 10-year, $1 million endorsement contract with a sporting goods firm, travels the world promoting racquetball and earns more than $100,000 in prize money each year.

But there are signs that Yellen's three-year domination of the top ranking may be slipping. Yellen, who is known as a slow starter, found himself severely tested by lower-echelon players in previous tour stops this season in California and Michigan.

"It used to be that players like Marty and I could cruise through our early matches," said Yellen. "But now, all the matches are difficult. You can't afford to let up for a second."

Yellen, of Southfield, Mich., also has begun to feel the heat of Hogan's revival. Hogan won the first tournament of this season and is playing better than he has in recent years.

Still, Yellen said, "I'm grateful for what he has given the sport. We grew up playing the game together, and I know he helped pave the way for my success."