Rafael Nadal broke John McEnroe's 34-year record on Thursday by winning his 50th consecutive set on clay at the Madrid Open.
But while the World No 1 cruised to a 6-3, 6-4 victory over Diego Schwartzman, Juan Martin del Potro, Maria Sharapova and Simona Halep all crashed out.
Nadal's straight-sets victory means he establishes a new Open era best for consecutive sets won on a single surface, passing McEnroe's 49 on carpet in 1984.
McEnroe also won the Madrid Open Indoor title that year and Nadal may be about to follow suit in the Spanish capital, with Austrian Dominic Thiem up next in the quarter-finals on Friday.
His unbeaten run is also perhaps a reflection of a lack of rivals, with Roger Federer, Novak Djokovic and Andy Murray, for different reasons, all posing little threat on clay over the past year.
"When my career is over, these are things that are going to be there forever," Nadal said.
"They are big records. It's difficult to be able to win 50 sets in a row. But I've done it. It's over.
Del Potro, however, will not join him in the last eight. The Argentinian led 4-0 in a third-set tie-break but still lost 3-6, 6-4, 7-6 (8/6) to Serbian qualifier Dusan Lajovic.
Lajovic will now face South Africa's Kevin Anderson, who overcame Philipp Kohlschreiber.
"I think I can improve a lot of things towards Rome and Roland Garros," Del Potro said. "I can level up my game. Right no...