Jannik Sinner's Wimbledon preparations suffered a blow as the world number one lost to 45th-ranked Alexander Bublik in the Halle Open second round.

Defending champion Sinner lost 3-6 6-3 6-4 to Kazakhstan's Bublik - his worst defeat by ranking since August 2023.

It is the first time Sinner has lost to someone other than world number two Carlos Alcaraz since August 2024.

The loss also ended the Italian's 66 match-winning streak against opponents outside of the top 20.

French Open champion Coco Gauff also suffered a surprise defeat in her first match of the grass-court season, losing 6-3 6-3 to China's Wang Xinyu at the Berlin Open.

World number 48 Wang ended Gauff's seven-match winning run just 12 days after her Roland Garros triumph.

Elsewhere in Berlin, world number one Aryna Sabalenka beat Swiss Rebeka Masarova 6-2 7-6 (8-6) in a match that took place across two days.

The Belarusian took the first set on Wednesday before bad light forced play to be suspended.

Sabalenka, beaten by Gauff in the French Open final, returned on Thursday and came back from a break down to wrap up a straight-set win.

Sabalenka will face Kazakh Elena Rybakina in the quarter-finals after the former Wimbledon champion beat Czech Katerina Siniakova 6-4 7-6 (7-5).

Marketa Vondrousova, who won the Wimbledon title in 2023, beat Russian Diana Shnaider 6-3 6-7 (3-7) 6-3.

Elsewhere at the Halle Open, Russian Andrey Rublev was another big name to fall, failing to convert two match points in a 3-6 7-6 (7-4) 7-6 (8-6) loss to Argentine Tomas Martin Etcheverry.

But German world number three Alexander Zverev recovered to beat Italian Lorenzo Sonego 3-6 6-4 7-6 (7-2).