Hingis led 4-0 in the first set and 5-2 in the second, which she thought she had won until the umpire failed to overrule a baseline call when she held a set point at 5-4, 40-30. But even though the majority of spectators voiced disapproval at that decision, few would begrudge Williams her 6-4, 7-6 victory. The 17-year-old American made up for her disappointment here last year, when she held two match points before losing to Hingis in the quarter-finals. Her older sister, Venus, stepped in to defeat Hingis in the semi-finals.
With Venus Williams due to continue the defence of the title against Steffi Graf in the second semi-final last night, the crowd was intrigued to see if at least one of the sisters would make it to tomorrow's final.
A storm delayed the start of Serena's match for two and three-quarter hours, and when play began it seemed that her thunder would be stolen. Having advanced to 40-15 with two consecutive aces, Williams proceeded to lose the next 12 points in a row, belting the ball into the net or wide of the lines when not being out-smarted by her 18-year-old opponent.
Down 0-3 after only nine minutes, Williams was given a brief respite by further rain. When play resumed, Hingis won her 13th successive point on the way to 4-0 - and then lost the next eight games in a row. The Swiss was blitzed by the power and range of Williams's shots, and was particularly deceived by the backhand.
Unable to convert either of two break points for 5-0, Hingis then had only one opportunity to save the first set, hitting a backhand over the baseline with Williams serving at 4-4. After holding for 5-4, Williams broke to love to take the set. By now she was confident enough to vary her power game with lobs and drop shots.
The American found the line with a cross-court backhand to save a break point in the opening game of the second set, and broke for 2-0, Hingis hitting a backhand beyone the baseline. But just as it appeared that Williams would run away with the match, Hingis broke back for 1-2 and forced her way to a 3-2 lead, Williams missing a backhand in the fifth game.
When Hingis broke again for 5-2 with a backhand volley, the crowd prepared to settled back to enjoy a third set. But this was not the kind of match to go according to plan, and Williams again fought her way back.
There was no doubting her right to break for 5-3, but a Williams forehand seemed to cross the baseline on Hingis's set point in the 10th game before the Swiss delivered a backhand long. Hingis broke again for 6-5, and recovered from 15-40 to deuce before losing the 12th game when serving for the set a second time.
"When you get a call like that on set point, you definitely don't love it," Hingis said afterwards. "But it happens. Of course, you're frustrated at that stage, but I should have won the set before that, and I had another chance to win the set again. You don't lose the match because of one point."
Williams, who was warned for breaking her racket in frustration as three break points slipped away from her in that game, gradually took control of the tie-break, which she won, 7-3, with a forehand down the line on her first match point.
Asked how worried she had been at 0-4 in the opening set, Williams said: "I have never given up in my life. It's not a part of me. I just kept thinking, `fight', and tried to get motivated. Before the match, Venus told me something, `if you get down just say this to yourself - I'm ok'.
"I started saying it. one point at a time. I have never beaten the No 1 player. Now you mention it, I guess it is my biggest victory."