BRIAN Watts continued his remarkable birdie spree yesterday to stay on course for the biggest victory of his career in the Kent Hongkong Open. Hitting the ball with authority and maintaining a smooth putting stroke, the 26-year-old American fired a three-under-par 68 in perfect conditions to add to his earlier scores of 63 and 69. His 54-hole aggregate of 200 is three shots clear of experienced Canadian Ray Stewart going into today's final round in the US$250,000 event - the opening leg of the 1993 Asian Tour. Although big-name stars Tom Watson, the defending champion, and Spain's Severiano Ballesteros both bettered par they appear too far back to make a charge for the US$41,650 first prize. However, with 1985 Hongkong champion Mark Aebli of America and Remi Bouchard of Canada, both within striking range of the lead, Watts is expecting a testing final day over the 6,732-yard, par-71 Composite Course layout. Said Watts: ''I've never been in this position in a big Open championship and I'm sure I'll be a little anxious going into the last round. ''I'm pleased to be at 13 under and I will just try and play the same as on the first three days.'' Continuing to strike his approach shots close to the flag, the Oklahoma State University graduate fired six birdies yesterday to add to the 13 he amassed over the first two days. ''I'd like to have another six birdies in the last round. If I did win it would be tremendous for me, but I don't want to get too far ahead of myself,'' said Watts, joint runner-up to American Ryder Cup player Ken Green at Fanling in 1990. The man most likely to catch Watts is his playing partner for the final day, 39-year-old Stewart. ''I will try and get off to a good start and put some pressure on him,'' said Stewart, who has twice been a runner-up on the US PGA Tour but lost his card in 1991. With only three bogeys in 54 holes, he believes he is playing consistently enough to record his first victory on the Asian Tour. Said Stewart: ''I'm striking the ball really solidly and this is the first time I've been in the hunt for a long time. ''I've been there before and I've got lots of experience but you never know what's going to happen until you get on the first tee and have your first swipe at the ball.'' Stewart's third-round 67 was made up of four birdies and 14 pars, the highlight being his four-iron tee-shot to the par-three fifth which finished 12 inches from the flagstick. He hit 17 greens in regulation, missing only the par-four 16th where his approach shot found the greenside bunker from where he got up and down to save par. Watts, meanwhile, recovered well after a bogey-six at the long third where he was forced to chip out sideways from the trees with his third shot. He holed from 15 feet for a birdie at the fourth and went under par after a pinpoint eight-iron approach to the seventh. A wayward five-iron tee-shot cost him a bogey at the short eighth, but he two-putted for a birdie after reaching the par-five ninth in two. Two slices of good fortune followed at the 12th and 13th. After a poor chip to the par-five 12th he holed from 20 feet for birdie and added another from 12 feet after his wedge to the 13th green took a kindly kick left towards the pin. ''I got lucky on those two holes,'' said Watts, who gave himself problems at the 14th when he opted to use a driver from the tee and his ball ran into the ditch crossing the fairway 270 yards away. He took a penalty drop but rescued a five before making his last birdie of the day from four feet at the 15th. Alone in fifth place on 207 is Australian Richard Backwell after a 67 yesterday, while 1988 Hongkong champion Hsieh Chin-sheng and Chen Tse-chung, both of Taiwan, Swedes Robert Karlsson and Nicolas Fasth and Northern Ireland's David Feherty are together on 208 in joint sixth. In equal third place overnight, European Ryder Cup player Feherty was expected to mount a strong challenge. But it proved a day of frustration for the Ulsterman as he struggled to find the form which brought him a 65 on Friday.