Rafael Nadal will face the toughest challenge of his Wimbledon campaign so far when he takes on American 11th seed Taylor Fritz on Wednesday.
The Spanish second seed is looking to take another step towards completing a calendar Grand Slam, having already won the 2022 Australian and French Opens.
A potential semi-final awaits against Australian Nick Kyrgios, who faces Chile's Cristian Garin on day 10.
Meanwhile, 2019 champion Simona Halep takes on American Amanda Anisimova.
Romania's Halep, the 16th seed, will face 20th seed Anisimova on Centre Court from 13:30 BST, with their match followed by Nadal versus Fritz.
"I did not think about [not dropping a set] until now but day by day it is better and better," said Halep, who is yet to be taken to a decider these championships.
"I am just looking forward to playing the next one and giving my best."
Australia's Ajla Tomljanovic takes on Kazakhstan's 17th seed Elena Rybakina in the day's other women's quarter-final.
Nadal faces Fritz challenge
This will be Nadal's first appearance in the quarter-finals at the All England Club in three years after Covid meant the 2020 edition was cancelled and the 36-year-old missed out last year through injury.
But the 22-time Grand Slam champion will come up against a player who has already got the better of him this year.
Fritz is playing in his first major quarter-final, having reached this stage with a 6-3 6-1 6-4 win over Jason Kubler of Australia.
And the 24-year-old will be full of confidence after beating Nadal to claim his first Masters 1000 title in the Indian Wells final earlier this year.
"In a personal way, for me to be able to be in quarter-finals after three years it's amazing for me so very, very happy," said Nadal.
"Every match is different. He is playing well and having a very good year including a first Masters 1000 title, against me by the way.
"But we will be in the quarter-final of Wimbledon, so what will I expect?"
Kyrgios eyes best Wimbledon run
Kyrgios beat Nadal on his Wimbledon debut in 2014, when he reached the quarter-finals, and will face the Spaniard in the semi-final if both players come through their last-eight ties.
The Australian is enjoying his best run at SW19 since that inaugural outing eight years ago and believes he has an "opportunity" to progress against world number 43 Garin, who surprised Australian prospect Alex de Minaur in the previous round.
"I was expecting to play Alex," said Kyrgios. "Then when I walked off the court and I got told it was Garin. It was surprising. I look at it as an opportunity but I need to do so many things before that match to get ready."
Garin saved two match points during that victory over De Minaur and says he thinks Kyrgios' world ranking of 40th does not do the 27-year-old's ability justice.
"Nick is very good player. For me, maybe the best serve on tour," he said. "I think Nick has to be seeded because he for me is one of the best players on the tour and on grass, obviously."
The match comes a day after it emerged Kyrgios is set to appear in court in Australia next month in relation to a claim of common assault.
Kyrgios has forged a reputation as one of his sport's biggest wasted talents, but Australian doubles great Todd Woodbridge says his compatriot has applied himself more than ever to be ready for this Grand Slam.
"Nick has prepared the best ever for a tournament here," he told the BBC.
"He spent time at home. He went to the Hunter's Hill tennis Club in Sydney with Lleyton Hewitt coming into winter and the courts were not that good but he put in a really big effort and his press conferences throughout the tournament were good."
Kyrgios reached two semi-finals at grass events in the lead-up to Wimbledon and enjoyed his first taste of Grand Slam success when he partnered countryman Thanasi Kokkinakis to the men's doubles title at the Australian Open in January.