What is bad for Monica Seles is good for Steffi Graf. Just as the early departure of world number one Martina Hingis will have aided third seed Lyndsey Davenport's march towards the final in the top half of the draw, so too will fourth seed Seles's early departure from Wimbledon yesterday help championship favourite Graf on her quest for an eighth singles title. Sixth seed Venus Willams is now the highest-ranked player remaining in Graf's half of the draw.

Seles was beaten 7-6, 7-6 by 17year-old Croatian Mirjana Lucic in the second biggest upset of the competition so far (after Hingis's loss to Jelena Dokic). Ranked 134th, compared to Seles's fourth in the world, the win was particularly sweet for Lucic given a year of family turmoil and injuries to her shoulder and elbow which kept her out of the game for three months.

Several years ago Lucic was regarded as a tennis prodigy in the mould of Anna Kournikova and Hingis but subsequently faded from the scene. She hasn't lost her self-belief, however.

"Not once did I believe I wouldn't win that match. It is definitely the best win of my career so far," she said.

Seles was always chasing the match despite the fact that on the two previous occasions the players had met (on hard courts), Seles won both matches 6-1, 6-4.

"If I could pinpoint one thing in the match that let me down, it was my returns," said Seles. "I'd tons of chances. On grass you can't let that happen.

"No, I don't think fitness was a factor today. It was my returns," she said, denying that her career had now come to a crossroads.

Another of the Wimbledon teenagers will have to depart in the next round as yesterday's winners Kournikova and Williams now face each other in round four for a place in the quarter-finals.

The 6ft 1in Williams dropped her serve in the opening game of her match against Sarah Pitkowski before tormenting the French girl with her full armoury of big serves and passing ground strokes to win 6-1, 6-1.

Williams, towering almost a foot over her opponent, even made efforts to approach the net and in doing so perhaps showed, more than anything, her unease at coming away from the baseline.

Moving Williams away from the back of the court is certainly something Kournikova will consider. The young Russian was forced to fight hard to win her first set 7-5 against Ines Gorrochategui, before the Argentinian was forced to retire with an injured shoulder at 3-1 down in the second set.

A physiotherapist had treated Gorrochategui on court before she initially struggled on and finally gave up.

"I think that I was playing very well to stay in at the beginning with her and then I just started playing better," said Kournikova. "Against Venus it is going to be a tough match, you know. She has a big serve, she's a big girl, so I have to just out-think her and try to play my game because grass is obviously not her favourite surface. So we'll see. I'll just have to play smarter," she added.

Kournikova will not be given much of a chance against Williams, whose name was the first on the lips of Graf when she was asked to name her main championship opponents, and while the Russian cannot match the American for strength, she could try to move the gangling teenager around the court. Williams, who rates her chances of winning the competition as "pretty good," claims that grass holds no fears for her.

"Anna has a solid backhand and forehand and serves well. Of course I do too. I like playing on the grass. But it's going to be the person who plays more aggressive, makes less mistakes and takes their chances that's going to win," said Williams.

Favourite Graf maintained her momentum in the bottom half of the draw and was untroubled again in defeating unseeded American Corina Morariu.