In the carefully considered and calibrated world of Iga Swiatek - in which her psychologist accompanies her to the hairdressers to offer an opinion on the optimal length of her ponytail - a fever and possible food poisoning just before Wimbledon was far from ideal.

But after an almost sleepless night on Thursday, which prompted her withdrawal from her semi-final in Bad Homburg on Friday, the world No.1 disclosed on Saturday that she will be physically ready for her opening match at the All England Club on Monday afternoon.

"I'm OK. I had a really bad night," she said. "We did measurements with my conditioning coach [on Friday morning]. They didn't really look good because I barely slept. I had a stomach ache, but I don't know if there was something wrong or not. Later in the day I felt OK, so I'm pretty sure it's going to be fine."

Just three weeks after winning a third Roland-Garros title, and her fourth Grand Slam overall, Swiatek is ready to go again, despite the illness. She's mentally primed for fresh Grand Slam competition, seeking a first title on the Wimbledon grass, where she is yet to go beyond the fourth round.

"I feel like I'm ready and pretty excited for the tournament," the Pole said ahead of her appearance on No.1 Court against China's Lin Zhu, who at world No.33 is the highest-ranked player who isn't seeded. 

Every tennis player has limited time to adjust their games from clay to lower-bouncing grass before The Championships. But Swiatek has even less than most, because she keeps going deep into Roland-Garros and winning titles.

But, fever and food poisoning aside, it sounds as though she has been productive between Paris and London, reaching a first WTA semi-final on grass in Bad Homburg and also using her practices to refine her grass court game.

Swiatek's primary focus has been on her footwork, which she regards as her strength on other surfaces. On grass, you can't just slide into shots, as she had been doing for weeks on clay.

"For sure, sliding is tricky here, so you have to slow down and stop before the shot in a different way," she said.

"I'm doing my best to just work on my skills. Last year I feel like we've done a pretty good job, with my coach, in terms of my touch and getting back slices and also playing the slice.

"This year I feel like we had more time to kind of focus on the basics, more time to also play matches. Yeah, I'm using that time as much as possible."

Every summer, Swiatek finds she can get into the rhythm of lawn tennis a little faster than the year before. But, as she noted this week, she feels as though she's "not close to being an expert on grass".

Some years, Swiatek has felt more at ease on the grass, such as when she won the Wimbledon girls' singles title in 2018. Other summers, less so.

"For sure, like deeply, I believe the best players, they can play on all surfaces. I want to become that kind of player who can play well on grass as well and feel comfortable there," she said.

Going into this summer's Championships, Swiatek seems to be more relaxed with being the best player in the world.

"Last year I felt a lot of pressure here because I was No.1 - I don't know. I feel like this time - actually, that was the first year where I could just focus on practising, actually learning a lot.

"So hopefully I'm going to be able to use that in my matches. For sure, getting used to the grass is always a tricky part because when you play well at Roland-Garros, then you have less time to prepare for Wimbledon. This year I feel like I've done a little bit more than for the past years."

Now she's feeling less pressure, Swiatek should be able to use her intuitive tennis ability more. "Last year, when I didn't play any matches before Wimbledon, it was hard to use my intuition because there was pressure.

"I felt like, 'I'm playing a Grand Slam, and I played so well in Roland-Garros that I should play well here as well'.

"But it's different. Your brain kind of has to feel the ball is bouncing lower. You can't think about things like that during the match. So I think this year, it's going to be a little bit easier for me to use my intuition a little bit more."

New this year:

See the draw like never before, with interactive Path to the Final view of the draw by clicking a player’s name on the draws page

See the projected Path to the Final of every player in the Gentlemen’s and Ladies’ singles draws with IBM Likely to Play

View how favourable or difficult a player's draw is, with IBM AI Draw Analysis