But Justine Henin-Hardenne's victory over Serena in the semi-finals at Roland Garros two weeks ago brought an end to the world number one's string of four consecutive Grand Slam titles -- all of which involved beating Venus in the finals.

Henin-Hardenne's win over Kim Clijsters in the French Open final also forced Venus Williams, winner of four Grand Slam titles, out of the top three for the first time in 18 months as the Belgian moved up to third in the rankings.

What happens at next week's Wimbledon could determine whether the American sisters' reign really has begun its demise or whether what happened at Roland Garros was nothing but a brief aberration.

Serena will be fired up to retain her Wimbledon crown and reassert her authority over the pretenders and would undoubtedly relish a return grudge match with Henin-Hardenne whom she could meet in the semi-finals.

The 21-year-old Serena was distraught after her 6-2 4-6 7-5 Roland Garros defeat, which was fought out in front of a tough partisan crowd who booed her throughout.

Serena had looked to have the match in her grasp at 4-2 and 30-0 in the third set when the umpire refused her the right to replay her first serve after the Belgian had raised her arm.

Serena was angry that Henin-Hardenne declined to intervene and the tearful American later added to the controversy by accusing her opponent of "lying and fabricating".

KEEP SMILING

The highly-competitive Serena is not one to let the events in Paris affect her future performances, however.

"It was a fight, that's all," she said after the defeat. "I am going to have to learn how to win. Got to keep smiling...I think if you keep smiling things work out."

Speaking about the match on returning to the United States, she said: "In a way there are things that you never forget. But there are things that you should forget.

"But it is hard, of course it is. I just try to think positive and tell myself I have got to get over that," she was quoted as saying.

The much more restrained crowds at Wimbledon will certainly help her recovery.

Elder sister Venus is looking further and further removed from the former world number one who two years ago won both Wimbledon and the U.S. Open for the second time.

Until last year the 23-year-old Venus was by far the more successful of the sisters.

Venus was the first of the two to win the grasscourt Grand Slam, beating Lindsay Davenport in 2000 before repeating the feat the following year by overcoming Henin in three sets, but her confidence appears to have crumbled while her younger sister's has soared.

UTTERLY DEJECTED

Her failure to progress beyond the fourth round of Roland Garros, knocked out by Russian teenager Vera Zvonareva, left her looking utterly dejected but she rejected the idea that her career was on the wane.

She had been hampered by a stomach injury in the weeks preceding the French Open and, by her own admission, had not done enough preparation.

"I've won majors before, I've won tournaments before, I've come from down in matches before," she said. "I have the experience to be successful. Now I just have to go on and do it."

If the elder Williams is to challenge once more for a Grand Slam title, she may have to spend more time on the game rather than on her other interest, interior design.

She has started her own company and often works at its Palm Beach Gardens headquarters.

But her early exit in Paris appears to have re-ignited her competitive spirit.

"I would love to win a major and I would love to finish number one," said Venus, who is in the opposite half of the draw to Serena.

"I suppose I'll just have to play more tournaments, play more matches. I think that will help me also to definitely get into the groove of things."