An emotional Coco Gauff said she will need to "make changes" to be successful at Wimbledon after she was knocked out in the first round on a day of shocks at the All England Club.

The American second seed was beaten 7-6 (7-3) 6-1 by Ukraine world number 42 Dayana Yastremska on a packed Court One under the roof.

Gauff, 21, was a contender for the title at SW19 following her triumph at Roland Garros less than a month ago.

But a performance strewn with double faults and unforced errors handed Yastremska a rare opportunity against the world number two and she grasped it with both hands to reach the second round.

Gauff teared up as she expressed "disappointment" at the loss and said she would do things differently in the build-up to the grass-court swing next time, particularly after a deep run at the French Open.

"I think it's just changing my playing style a little bit, which is difficult," she said.

"I have faith that if I can make these adjustments, I can do well here. I really do want to do well here.

"I'm not someone who wants to write myself off grass this early in my career, but I definitely need to make changes if I want to be successful here."

The shock result follows first-round exits for fellow top-five seeds Jessica Pegula and Zheng Qinwen on day two at the Championships.

American third seed Pegula lost 6-2 6-3 to Italy's world number 116 Elisabetta Cocciaretto while Olympic champion Zheng went down 7-5 4-6 6-1 to Katerina Siniakova.

Just three and a half weeks ago Gauff was on top of the world, having lifted the trophy at Roland Garros after beating world number one Aryna Sabalenka.

But a lacklustre performance laden with mistakes on her unfavoured surface saw the two-time major winner head out early against the unseeded Yastremska, leading her to question her build-up to the grass-court major.

"I just feel like the surface, I maybe could have used more matches," she said.

"If you go deep in Roland Garros, you're debating: 'do I rush and play that week, or do I take time and play the week before?' It's a tricky thing.

"It's like finding the puzzle. I don't like to play the week before. It's a quick turnaround, so I think just trying to learn whether it's better to train more and maybe play Bad Homburg or Eastbourne.

"If that time comes around again I'll approach it differently."

Since winning her first title on the Paris clay last month Gauff has played just one match, a first-round defeat by qualifier Wang Xinyu of China at the Berlin Open.

In that match, she was plagued by double faults and those demons were back to haunt her again at SW19.

Gauff recorded nine double faults and 29 unforced errors compared with just six winners and struggled against Yastremska's aggressive style and powerful ground strokes.

Success on grass continues to elude her with Wimbledon the only Grand Slam where Gauff is yet to reach the last eight.

Pegula said her first-round exit earlier on Tuesday was her "worst result of the year" as she was beaten by a player ranked 113 places below her.

The 31-year-old had heavy strapping on her right knee but said that did not bother her as she was dismantled in just 58 minutes on Court Two by Cocciaretto.

"This is definitely probably the worst result I've had all year," the American said.

"I've been winning lots of matches. It's just all about it having to come together for two weeks. Sometimes it doesn't quite all align when you need it to."

Pegula has only once gone beyond the quarter-final stage of a major - at last year's US Open where she lost to Aryna Sabalenka in the final - and has gone out before the last eight in all three Grand Slam tournaments since.

This marks her worst performance at a major since the 2020 French Open.

Less than three hours later she was followed out of the door by Chinese fifth seed Zheng after a grass-court lesson from doubles champion Siniakova.

Siniakova, who has won the Wimbledon women's doubles title three times, showed her grass-court pedigree to ensure Zheng's challenge ended at the first hurdle for the third year in a row. It was the Czech who also knocked her out at the same stage two years ago.

Polish eighth seed Iga Swiatek advanced with a comprehensive 7-5 6-1 victory over Russia's Polina Kudermetova.

Teenager Mirra Andreeva was also a 6-3 6-3 winner against Egypt's Mayar Sherif while 2022 Wimbledon champion Elena Rybakina cruised through with a 6-2 6-1 victory over Armenia's Elina Avanesyan.