Carlos Alcaraz of Spain serves against Nicolas Jarry of Chile (not pictured) during their match at the Wimbledon tennis championships in London, England, July 8, 2023. (Photo: CFP)

Top seed Carlos Alcaraz of Spain survived his first big test at this year's Wimbledon on Saturday and women's champion Elena Rybakina of Kazakhstan doused British hopes as the big names moved through the gears into the second week.

Despite more rain on day six, the slow-burner tournament began to heat up with women's second seed Aryna Sabalenka of Belarus, two-time champion Petra Kvitova of Czech Republic and last year's runner-up Ons Jabeur of Tunisia all reaching the last 16.

In the men's draw, third seed Daniil Medvedev and fifth seed Stefanos Tsitsipas both swept through while 2021 runner-up Matteo Berrettini of Italy set up a showdown with Alcaraz.

Italy's Matteo Berrettini celebrates defeating Germany's Alexander Zverev, who is sitting on the bench, after their match at the Wimbledon tennis championships in London, England, July 8, 2023.

World number one Alcaraz has raised expectations sky high after his title at Queen's Club last month and a showdown next Sunday against seven-time champion Novak Djokovic is already being penciled in by many.

What is sometimes forgotten, however, is that the 20-year-old Spaniard is playing just his fourth tournament on grass.

That showed at times against Chile's Nicolas Jarry as he was pushed out of his comfort zone.

But despite at one stage heading towards a fifth-set decider he managed to land the telling blows when required to emerge with a 6-3, 6-7(6), 6-3, 7-5 victory on Center Court.

With the big-serving Berrettini up next, Alcaraz, who was a break down in the fourth set, said Saturday's test was just what he needed.

"This match made me a lot of confidence honestly. Every match that I win on Centre Court is better for me to get into this court, this atmosphere," he told reporters.

Berrettini, unseeded after a season plagued by injury, looked razor-sharp as he beat former world number two Alexander Zverev of Germany in a high-octane Court One clash which ended under the roof after rain fell late on Saturday.

"I honestly don't know. It feels unbelievable. It is something I didn't think could happen. It must be something special about this place," Berrettini said.

Elena Rybakina of Kazakhstan celebrates after her match with Britain's Katie Boulter (not pictured) during the Wimbledon tennis championships in London, England, July 8, 2023.

Rybakina ensured a demoralizing 48 hours for Britain as she demolished Katie Boulter 6-1, 6-1 to end home hopes in the singles. On Friday, Andy Murray, Cameron Norrie and Liam Broady all exited the men's singles.

With Rybakina suffering with a virus at the French Open and having a disrupted preparation, British number one Boulter was tipped to cause a huge third-round shock.

But she lasted only 57 minutes as Rybakina sent out an ominous warning to those wanting her title.

Next she will face Beatriz Haddad Maia, who is aiming to become the first Brazilian woman to reach the last eight here since the great Maria Bueno in 1968.

Second seed Sabalenka is also in the groove heading into the second week after a 6-2, 6-3 defeat of Anna Blinkova of Russia.

Sixth seed Jabeur, desperate to make up for last year's near miss, was in trouble against Canada's Bianca Andreescu a former U.S. Open champion. But she found a way to a 3-6, 6-3, 6-4 win to set up a last-16 clash with Kvitova.

Kvitova, bang in form on grass after a title run in Berlin last month, beat Serbia's Natalija Stevanovic 6-3, 7-5.

Holger Rune of Denmark celebrates his fifth-set tie-break victory against Alejandro Davidovich Fokina of Spain (not picture) after their match at the Wimbledon tennis championships in London, England, July 8, 2023.

The match of the day saw Denmark's eye-catching 20-year-old Holger Rune, seeded six, delight a packed Court Three crowd as he saved two match points to beat Spain's Alejandro Davidovich Fokina 6-3, 4-6, 3-6, 6-4, 7-6(8).

Rune battled back from 5-8 down in the final-set tiebreak and was helped at 8-8 when his opponent bizarrely sent in an underarm serve which Rune demolished for a winner.

"It was obviously surprising, but I don't think he even bounced the ball, so I was, like, I was aware that something was different," Rune told reporters.

Big-serving American Christopher Eubanks continued his fairytale progress as he won three tiebreaks against Australian Chris O'Connell, taking his ace count to 72 for the week.

He will next face Tsitsipas, who beat Serbian Laslo Djere 6-4, 7-6(5), 6-4.