Wimbledon champion Elena Rybakina suffers surprise defeat against Donna Vekic

Rybakina, the tournament's second seed, was on the back of a nine-match unbeaten run - with eight of those victories having come on grass - as she warms up for the defence of her title at the All England Club next month.

The world number three looked to have put herself on course for the quarter-finals after taking the opening set on a tie-break.

However, Vekic fought back with a break of Rybakina™s serve in the sixth game of the second set to go on and level the match.

With the decider locked at 3-3, Vekic secured another crucial break before going on to serve out for victory in just over two hours and 15 minutes.

"I'm really happy to not only beat her, but to be in the quarter-finals," world number 23 Vekic said afterwards, quoted on the WTA Tour website.

"She was serving really big, so I was like: 'just stay with her, your chances will come' and they did."

Vekic will next face lucky loser Elina Avanesyan, who came back to defeat Anna Blinkova in three sets, 1-6 6-2 6-3.

Earlier on Wednesday, Aliaksandra Sasnovich upset former world number one Victoria Azarenka in their rain-delayed first-round match to progress 6-4 6-4.

Sixth seed Maria Sakkari beat Alize Cornet 6-4 6-2 and Marketa Vondrousova saw off 2019 US Open champion Bianca Andreescu 7-6 (0) 7-5.

Veronika Kudermetova secured a showdown against top seed Aryna Sabalenka after she won through 6-4 6-2 against Zheng Qinwen.