Jankovic, though, had her eye on the big prize this year. Having turned down the chance to team up with Murray once again to defend their title, she said she wanted to concentrate on the singles. The more the big names topple, the wiser that decision is looking – although yesterday she had to overcome a tough challenger as well as a knee injury to progress to the fourth round.

She went for an MRI scan last night and will decide today whether or not she continues depending on how well her knee has recovered. "It happened near the beginning of the first set. I slid and my leg went straight and then bent so quickly, and it was a sharp pain in that moment. But then, you know, I continued to play and play, and it was getting worse and worse. Especially because on grass you have to stay low every time. You have to bend a lot. In the third set, I was struggling a little bit, but somehow came through.

"It's a little bit swollen at the moment, but I don't think it's that bad. I didn't break anything so I'm able to walk and move on the court. I have pain on it, but, you know, I don't play tomorrow, and hopefully now I can get some treatment and feel better for my next match."

It is unlikely to be as tough as the one she came through yesterday. Her Danish opponent is another of those on the tour who looks like an angel but is possessed by the demon desire to win. Seeded 31 for the tournament, this was only her second year of Grand Slam appearances but having failed to get beyond the second round in any last year, she has already underlined her improvement.

Still only 17, she has a sporting pedigree thanks to a father who played professional football in Poland and in Denmark and a mother who starred in the Polish national volleyball team, while she made her tour debut eight days after her 15th birthday, so it perhaps should not have been a shock that the Centre Court arena did not daunt her. Neither did Jankovic. The highest-ranked female left in the singles after the departure of both Ana Ivanovic and Maria Sharapova in recent days, the Serbian also has the grass court credentials, but that reputation seemed to stimulate her young and feisty opponent rather than unnerve her.

Holding her serve throughout the first set, she broke the world No.3 twice to take the opener 6-2. It took five attempts in the eighth match to finally seal the deal but she held her nerve.

It was a sign of Wozniacki's mental strength. She has made a quick transition to life on the tour, moving quickly into the top 100 in her first full year before journeying deeper into events. Getting to the semi-final of the Japan Open in Tokyo last year helped her make the jump even further up the rankings.

But the warnings from previous days had been observed by Jankovic. Having witnessed the summary dismissal of the players around her in the higher echelons, she refused to let the young pretender get too firm a footing as the second set got under way. In Wozniacki's first service game she immediately applied the pressure and having failed to capitalise on the first break point she benefited from a late line call which resulted in a double fault for the Dane and another break opportunity for Jankovic. It highlighted the weakness the underdog still has in that second serve and as Wozniacki charged the net, the Serbian played an unstoppable passing shot cross court to take the initiative.

Twice there was the chance to get back into it. In the sixth game the breakback was on when Jankovic let her in to take it to 30-40. It was a solitary shot at it and she hit the forehand long. Wozniacki was then the one clinging on in the following game, having to produce a big first serve to prevent a double break. As the momentum yo-yoed the teenager had two further break points, taking her match tally to 10 at that stage, but Jankovic again held on and took the second set As they returned to their seats the world No.3 called for her medical time out. The jarred left knee was troubling her and her trainer strapped it so tightly she complained she could not bend her leg properly. But Jankovic, despite the limping between points, moved well enough in rallies to get a break in the first game in the deciding set.

But while some lower ranked players may have crumbled at that, Wozniacki refused to give up. There were more breaks by both players, the majority were in favour of Jankovic, though, which allowed her to take a 5-2 lead and serve for the match – two hours and five minutes after they had started.