HONG Kong Davis Cup veteran Colin Grant pulled off a minor upset in the South China Open final at King's Park yesterday with a straight sets triumph over top-seeded Australian Mark Jeffrey to retain the Coca-Cola trophy. The 27-year-old, who breezed into the final without dropping a set, survived two set points in the opener for a 7-6, 6-2 victory. ''I'm a bit surprised to win the tournament because I haven't had any serious training for it,'' said an elated Grant, whose next target is to win the Chinese Recreation Club Open. ''But maybe it's because I haven't been in competitions for so long, I'm a lot keener when I go into a match and I'm also enjoying it more.'' Games went with serve throughout the first set and Jeffrey, ranked 250th in the world as an 18-year-old professional eight years ago before his career was curtailed by a back injury, was on the verge of clinching it with two set points in the tie-break. However, he let Grant off the hook with a double fault and then hit a cross-court wide. Grant put on the pressure and won the next two points to clinch it 8-6. Jeffrey's game went to pieces after Grant broke him in the fifth game for a 3-2 lead and then reeled off the next three games for the match. ''I know I'm very unfit because I haven't actually played serious tennis for nine months,'' said the 26-year-old Australian, who was hired as a training partner by promising local junior John Hui early this year. ''I've only been hitting out with John and taking him to tournaments. My job now is to see him do well.'' Willy Chan whitewashed 14-year-old Yan Sin-man in the women's final.