Center Court a Center Stage for Open Dramas THE beauty of this year's United States Open tennis championship, which ended Sunday, is that spectators got to see the sport's very best players in the finals (Pete Sampras prevailed over Andre Agassi and Steffi Graf staved off Monica Seles). That might not sound so unusual, but it doesn't happen that often. The reasons: It's tricky even for top-ranked players to make it through to the final of a two-week Grand Slam tournament like the Open, and the never-ending tennis ''season'' has so many events that the best players are sometimes like ships passing in the night. This year's Open was special, in holding to form and producing the classic matchups. (Actually a fifth 1995 duel.) And on this occasion, these engagements had a depth that transcended the players' computer-generated rankings. The women's final, in particular, was a theater of personal dramas. Both players were battling, not only to win a championship, but to overcome. For Seles, reaching the final was a clear statement that her comeback was complete and that a 2-1/2-year absence from tennis could not suppress her joy in playing. For Graf, the challenges were just as great, both physical and mental. Her father, Peter, was recently jailed in Germany on charges of tax evasion, a distraction that did not keep her from her self-appointed tennis rounds and a gutsy 7-6, 0-6, 6-3 victory over Seles. In the men's final, we saw two guys with an absence of malice but an abundance of admiration for each other as players and people. Sampras won Wimbledon in July for the third straight time, but the summer belonged to Agassi, who rolled into Sunday's championship on a 26-match winning streak that included tournament victories in Washington, Montreal, Cincinnati, and New Haven, Conn. A year earlier, he had ignited his stagnating career by becoming the first unseeded player since 1966 to win the US title. The two Americans entered Sunday's final evenly matched, with eight career wins apiece against each other, including a 2-2 split in Grand Slam finals. This time Sampras had his supersonic serves working (24 aces) and when the ''play of the day'' had to be made, he made it on the last point of the first set. After trading more than 20 shots from the baseline, Sampras unleashed a scorching backhand that left Agassi flatfooted. Sampras called it ''one of the best points I've ever been part of,'' a linchpin, as it turned out, in his 6-4, 6-3, 4-6, 7-5 triumph. Domestic violence and double zero THE Boston Celtics face a dilemma. The jersey number the team would logically retire next - and the first raised to the rafters of the new FleetCenter - is double zero, which belongs to Robert Parish. But according to a recent special report in Sports Illustrated, Parish allegedly committed acts of domestic violence. Unless this cloud is removed, Celtic fans presumably would feel uneasy about saluting Parish. Based purely on playing ability, which is what counts in retiring numbers, Parish clearly deserves the same recognition accorded Larry Bird and Kevin McHale, his ''Big Three'' front-court mates. On the other hand, honoring Parish is at best an awkward proposition, one the Celtics probably would like to delay. Because Parish is still playing with the Charlotte Hornets, the Celtics don't have to make any decision until he retires. That could occur almost anytime, although it appears that the 19-year veteran intends to play at least another season. The retirement of Parish's jersey number, while a Boston matter, raises an increasingly common question for sports fans everywhere: Should an athlete's personal life influence professional admiration? Or put another way, can people compartmentalize their heroes? Touching other bases * Pop quiz: Last season, an annual award for the top football player from a black college was instituted. The trophy bears the name of a coach whose team plays Hampton University at the Meadlowlands in New Jersey Saturday. Name the coach and his school. (Answer at end.) * Major-league baseball already knows it has a treasure in Cal Ripken, the Energizer Bunny who surpassed Lou Gehrig's ironman record last week. But imagine how grateful the sport must be for his presence during this trying year. Fans who have flocked to see him play know they're seeing a future legend, a model citizen, and a one-man metaphor for the day-to-day consistency that is an important virtue in baseball and in life. * And more Ripkenmania: Cal was born at the mouth of the Susquehanna River on Maryland's Chesapeake coast. The river starts less than a mile from Cooperstown, N.Y., home to the Baseball Hall of Fame. And to think that Ripken set the consecutive-games record playing shortstop, one of baseball's most hazardous positions, given the mayhem that occurs at second base. * This writer surmises that the Olympic-motif Swatch wristwatches ($40 to $50) will be big sellers during the next year. They are among 200 officially licensed Atlanta Olympic Games products. (See photo.) * Quiz answer: Eddie Robinson. Grambling (La.) State University's coach, owns the all-division record with 398 victories. He is in his 54th season on the job, all at Grambling.