DUBAI (AFP) - Venus Williams edged ahead 10-9 in the family tussle with younger sister Serena to reach the final of the Dubai Open on Friday where she will have the opportunity to capture her second successive title in the Gulf. The Wimbledon champion won 6-1, 2-6, 7-6 (7/3) against the world number one, producing a sensational display of serving in the first set, and an ability to fight and win crucial points at the net in a fluctuating third. These are qualities which will make the American hot favourite to beat Virginie Razzano, the surprise finalist from France, and follow up the WTA Championships title she won in nearby Doha in November. Asked how difficult she still found it to play against her sister, Venus replied: "You know I am always the big sister. I have to stay focussed when I am out there. I can't worry too much whether she is okay. She's an unbelievable player. So I have two problems out there." It looked increasingly likely that Venus would win for the fifth time in their last seven meetings as the knee problem which caused Serena to pull out of the semi-finals in Paris last week appeared gradually to be getting worse. Depsite this, the Australian Open champion continued to play at a high level, and the final set was the best one, everything hingeing on a tie-break for only the second time in their 19 encounters. It was during this exciting climax to one of the best matches between them that Venus' serving returned to somewhere near the levels which had enabled her to go through the entire first set without dropping a point behind it. But the final set also depended greatly on a Hawkeye decision which prevented Serena from taking a 4-2 lead, and perhaps continuing the second set momentum which had turned the contest around. She countered Venus' enterprising approach and well-placed volley with a topspin lob which landed near the baseline and was called in. Venus, who had earlier twice eschewed appeals to the computerised replay system when it seemed she might have profited by doing so, could not this time resist. The ball was two inches out, and six rallies later - one of which was the rally of the match, with a brilliant Venus sequence at the net - the struggling older sister had broken back. After that she looked the more likely winner, moving the better, producing more net attacks, and serving the better, something which saved her in the eleventh game with timely aces on break points. "I thought Venus played very well, though I didn't serve that great," said Serena, referring to her six double faults in the first set. "But I look forward to getting fitter. I wasn't at my best physically but this schedule is the most amount of tennis I have played for a long time." Razzano, the world number 58, put out Kaia Kinepi, the 16th-seeded Estonian, 6-1, 6-2 to reach the final. "I try to make a lot of pressure all the time and play aggressive," said the flat-hitting, high-intensity Frenchwoman.