-- If you climbed high enough in the grandstand of Court 4 at the National Tennis Center on Tuesday afternoon, you arrived at a spot where you could monitor the action on two practice courts at once. Below was James Blake, hitting with sparring partner Bo Hodge, a former all-American at Georgia. To the left, on the more intimate Court P-1, was Andre Agassi, swapping groundstrokes with coach Darren Cahill.

While the hordes made their way to Arthur Ashe Stadium for the U.S. Open's featured matches, dozens scaled the side court's grandstand to feast on this appetizer, bobbing their heads from one court to the other as Blake and Agassi tuned up for their much-anticipated quarterfinal Wednesday night. How fans will react when Agassi and Blake stride onto center court will be among the more intriguing story lines in a match that's already replete with drama.

"James is the story," says four-time U.S. Open champion John McEnroe, 46, who is providing TV commentary. "But Andre is our living legend that's still playing, trying to win one more Slam before he gives up. I think it's going to be a little difficult for the fans -- maybe a little bit similar to when Venus and Serena [Williams] play, the fans don't know who to root for."

McEnroe sees the all-American quarterfinal as sure to spark interest in the men's game, particularly after the deflating first-round ouster of Andy Roddick, the country's best hope of reclaiming the title from top-seeded Roger Federer.

Agassi, a two-time U.S. Open champion, is the sentimental favorite. One of the greatest to play the game, he has also become the sport's most-respected ambassador. With the loss of Roddick and second-seeded Rafael Nadal (upset by Blake), Agassi is also the highest seed (seventh) remaining in the bottom half of the draw, which in theory presents him with an easy path to Sunday's final.

Standing in his way is Blake, one of Agassi's biggest fans, who is having the tournament of his life. And his resurgence, following a season marred by illness, injury and loss, has been roundly cheered by fans and fellow competitors.

As McEnroe sizes it up, Agassi boasts more experience, a better backhand and a stronger game. But Agassi has had to exert more energy to get to the quarterfinals, slogging through a five-set match Monday.

Blake's biggest asset is his speed, freshness and new-found calm that's helping him plug away in difficult matches rather than self-destruct, as he likely would have a few years ago.

"It's the physical part for Andre: Is Andre going to be fresh enough?" McEnroe says. "And it's the mental part for James: Is it going to be too overwhelming for him? He's playing a guy he really looks up to and respects. A lot of times that's like being down a break."