CARMEN Hajjar endured a roller-coaster ride to sudden-death victory in the JAL Hongkong Open women's amateur championship at Fanling yesterday. The 26-year-old Australian clinched a heart-stopping triumph on the third extra hole after blowing a five-stroke lead on the back nine and then watching Japanese opponent Yukiko Oita throw away her own chance of victory on the final regulation hole. ''I hadn't been in that type of situation before and I was so incredibly nervous,'' said Hajjar, a scratch handicapper from Brisbane who had never previously travelled beyond her home country and for whom shopping was one of the main purposes of the trip. Four shots clear of her closest challengers and five in front of Oita going into the last round, Hajjar looked set to coast to a runaway success as she toured the front nine of the Eden Course in even-par 35. With Hongkong's Joann Hardwick firing a 76 to finish third, Oita emerged as the only serious threat. And when Hajjar faltered on the back nine, the experienced three-handicapper from Shinyu Country Club in Kobe pounced. Putting tentatively, Hajjar saw her lead reduced to just one with three holes remaining. Oita drew level with a birdie at the long 16th and when Hajjar trudged off the same green 10 minutes later with a six on her card the Japanese was in front for the first time. However, Oita came unstuck at the last where she three-putted for a bogey six and a round of 72 leaving the door open for Hajjar whose 12-foot putt for victory missed on the low side. She tapped in for a 77 and headed back to the first tee for the play-off. Both women scrambled pars at the first and made threes at the short second where Oita's 25-foot birdie putt missed by a whisker. And so to the par-five third where Oita's approach kicked left into the pond short of the green. She took a penalty drop and pitched on for four while her opponent was on the back fringe in three. Hajjar left her first putt 15 feet short and had to settle for a six. Oita, whose bold putt for par lipped out, faced a four-footer to keep the play-off alive. She failed and Hajjar was reprieved.