They were juxtaposed again yesterday, practicing on opposite ends of adjacent courts. While Pete Sampras worked on his dominating serve with fellow tour player Vladimir Voltchkov, Andre Agassi was honing his fearsome forehand with coach Brad Gilbert.

The two were almost in synch, but not quite – just like through much of their careers. For years, Sampras was the king of grand slams while Agassi was portrayed as a clown prince. Now it’s Agassi smashing returns on the way up while Sampras seemingly struggles to remain in the game.

Tonight at Arthur Ashe Stadium, the second-seeded Agassi will try to stomp out a suddenly energized Sampras, a 10th seed with a 17-tourney winless streak who has something to prove.

Their personalities reflect what they would allow regarding the most anticipated men’s quarterfinal match in years.

“It should be a good one,” Sampras said as he ducked into the players’ locker room after his workout.

Agassi was unable or unwilling to disguise the gravity of the rivalry. “We have a lot of respect for each other,” he said. “A lot of years out there.

“Many battles, many memories. Certainly [tonight] will be a new one.”

The two American superstars, who have sized each other up since they first played as adolescents in Northridge, Calif., aren’t necessarily heading in opposite directions. They both have the same goal, but many believe only Agassi is poised to achieve it.

While the 30-year-old Sampras owns 13 grand slams to the 31-year-old Agassi’s seven, there’s been widespread talk that Sampras is on the downside of his career. On Monday night, he came out firing like a pistol against Pat Rafter, erasing him in four sets behind a partisan crowd that fed on Sampras’ rare display of emotion.

“There are certain times I do show emotion,” Sampras said after the match. “It’s not too surprising when you win a big match like that, play a great match point.”

Agassi trails 17-14 in the series, but he’s won the last three matches.

“The most important one is the next one,” said Agassi, who last beat Sampras 6-4, 6-2 in the finals of the Mercedes-Benz Cup in L.A. on July 29. “That’s how it always feels.”

Sampras’ road to the quarterfinals

First round – def. Julien Boutter, 6-4, 7-6 (4), 7-6 (6).

Second round – def. Andre Sa, 7-6 (4), 6-4, 6-3.

Third round – def. Mikhail Youzhny, 6-3, 6-2, 6-2.

Fourth round – def. Patrick Rafter (6), 6-3, 6-2, 6-7 (5), 6-4.

Andre Agassi’s road to the quarterfinals

First round – def. Mike Bryan, 6-4, 6-1, 6-0.

Second round – def. Nicolas Massu, 6-7 (4), 6-4, 6-2, 7-6 (1).

Third round – def. Ramon Delgado, 7-5, 7-6 (5), 6-3.

Fourth round – def. Roger Federer (13), 6-1, 6-2, 6-4.

PETE VS. ANDRE THROUGH THE YEARS

1989

Rome, clay-outdoor – Agassi wins, 6-2, 6-1.

1990

Philadelphia, carpet-indoor – Sampras wins, 5-7, 7-5, retired.

U.S. Open, hard-outdoor – Sampras wins, 6-4, 6-3, 2-6.

ATP Finals, carpet-indoor – Agassi wins, 6-4, 6-2.

1991

ATP Finals, carpet-indoor – Sampras wins, 6-3, 6-1, 6-3.

1992

Atlanta, clay-outdoor – Agassi wins, 7-5, 6-4.

French Open, clay-outdoor – Agassi wins , 7-6 (6), 6-2, 6-1.

1993

Wimbledon, grass-outdoor – Sampras wins, 6-2, 6-2, 3-6, 3-6, 6-4.

1994

Lipton-Key Biscayne, hard-outdoor – Sampras wins, 5-7, 6-3, 6-3.

Osaka, hard-outdoor – Sampras wins, 6-3, 6-1.

Paris Indoor, carpet-indoor – Agassi wins, 7-6 (6), 7-5.

ATP Finals, carpet-indoor – Sampras wins, 4-6, 7-6 (5), 6-3.

1995

Australian Open, hard-outdoor – Agassi wins, 4-6, 6-1, 7-6 (6), 6-4.

Indian Wells, hard-outdoor – Sampras wins, 7-5, 6-3, 7-5.

Lipton-Key Biscayne, hard-outdoor – Agassi wins, 3-6, 6-2, 7-6 (3).

Canadian Open, hard-outdoor – Agassi wins, 3-6, 6-2, 6-3.

U.S. Open, hard-outdoor – Sampras wins, 6-4, 6-3, 4-6, 7-5.

1996

San Jose, hard-indoor – Sampras wins, 6-2, 6-3.

Stuttgart Indoor, carpet-indoor – Sampras wins, 6-4, 6-1.

ATP Finals, carpet-indoor – Sampras wins, 6-2, 6-1.

1998

San Jose, hard-indoor – Agassi wins, 6-2, 6-4.

Monte Carlo, clay-outdoor – Sampras wins, 6-4, 7-5.

Canadian Open, hard-outdoor – Agassi wins, 6-7 (5), 6-1, 6-2.

1999

Wimbledon, grass-outdoor – Sampras wins, 6-3, 6-4, 7-5.

Los Angeles, hard-outdoor – Sampras wins, 7-6 (3), 7-6 (1).

Cincinnati, hard-outdoor – Sampras wins, 7-6 (7), 6-3.

ATP Finals, hard-indoor – Agassi wins, 6-2, 6-2.

ATP Finals, hard-indoor – Sampras wins, 6-1, 7-5, 6-4.

2000

Australian Open, hard-outdoor – Agassi wins, 6-4, 3-6, 6-7 (0), 7-6 (5), 6-1.

2001

Indian Wells, hard-outdoor – Agassi wins, 7-6 (5), 7-5, 6-1.

Los Angeles, hard-outdoor – Agassi wins, 6-4, 6-2.