INJURED Dutchman Richard Krajicek quashed fears of his imminent withdrawal after ending John McEnroe's hopes of a dream return to big-time tennis with a 6-4, 6-4 victory in the $5.4 million Marlboro Championships at Victoria Park last night. The world number 11 and second seed was confident of lining up in tomorrow's semi-finals despite withdrawing from last night's doubles competition because of pain in his knees. Krajicek became the first player to reach the semi-finals, winning both matches in the Blue group, which also included injured Australian Mark Woodforde. But soon after beating McEnroe, Krajicek was unable to partner Peru's Jaime Yzaga in a late-night doubles match, giving a walkover to Japanese pair Ryuso Tsujino and Daijiro Furusho, who qualify for the semi-finals from the Libra group. The other three singles semi-final places will be decided today, while Krajicek has a day to rest. Krajicek caught McEnroe on a few points with perfect lobs and accurate passing shots and his winning shot was a delicate drop shot that his opponent, in his prime, would have been proud of. For 34-year-old McEnroe, the defeat did little to hasten a decision on whether or not he would officially retire from tennis. ''I haven't announced officially that I have retired, but at the same time, I'm not playing regularly. I'm in limbo at the moment,'' said McEnroe. ''I must think seriously on whether or not to continue. I'm not getting any younger. ''There are guys who are younger and eager to win and who consider it a notch in their belts to beat me. I never thought I should have won the match, but not being match-fit hurts.'' Although out of the singles, McEnroe had no regrets about playing in Hong Kong, which he feels should be given a higher profile in international tennis. McEnroe can now concentrate on his doubles hopes with French partner Henri Leconte. The pair today take on the unbeaten world champions from Australia Todd Woodbridge and Woodforde in the Scorpio group, needing nothing short of an emphatic win to reach the semi-finals. Top seed in the singles, Sweden's world number six Stefan Edberg, needs only one set today off Spain's Carlos Costa to advance to the semi-finals from the Red group. Costa was yesterday beaten 6-4, 6-0 by Woodbridge, who lost to Edberg in straight sets on the opening day. American third seed Todd Martin needs a victory over South African Wayne Ferreira in the Silver goup to book his place in the semi-finals. Martin had a tough 6-7 (4-7), 7-6 (7-5), 6-3 victory over Sweden's Anders Jarryd last night in his opening singles match. Jarryd's semi-final hopes lies with a victory for the off-form Ferreira. Krajicek, who won his first tournament in Hong Kong two years ago, held his awesome serve for the entire first set, achieving the crucial break against McEnroe in the fifth game to go 3-2 up. The next time he broke, to lead 1-0 in the second set, it appeared that the set, and the match, was his for the taking. McEnroe, however, responded to the support of the 3,000-odd fans, by breaking Krajicek for the first time to level the set at 2-2 when his opponent hit a rare double fault. Krajicek double-faulted again two games later on break point, but he broke McEnroe twice more, restoring his one-break advantage to win the match in 86 minutes.