NEW YORK, AUG 31: The US Open received a jolt today when four-time champion Pete Sampras was forced to withdraw before playing a match because of a back injury.Sampras suffered a small herniated disc in his back according to Dr Brian Hainline, medical director of the US Open. ``It's not allowing him to move as he should,'' Hainline said.Sampras withdrew from a tournament in Indianapolis two weeks ago because of a hip injury. He apparently injured his back during practice on Sunday and asked US Open officials to delay his first-round match until tomorrow.Then today, he pulled out.``The good part is that we discovered it early,'' Hainline said. ``A large herniated disc could've jeopardized his future, so it's good we caught it early.''The withdrawal of Sampras, the Wimbledon champion, makes Andre Agassi the tournament favourite. The second-seeded Agassi began his quest under the lights last night at Arthur Ashe Stadium.Seeking his third consecutive Grand Slam tournament final, the second-seededAgassi capped the opening day of the year's final Grand Slam tournament last night with a 6-1, 6-1, 6-3 thrashing of Sweden's Nicklas Kulti. In the first upset of Day Two, sixth seed Tim Henman of Britain lost in straight sets to Guillermo Canas of Argentina 6-7, 4-6, 3-6.
