LONDON -- Rafael Nadal guaranteed he will stay No. 1 in the rankings after Wimbledon as he reached the fourth round with a 6-1, 6-2, 6-4 victory over 19-year-old Australian Alex De Minaur on Saturday.
Nadal, the No. 2 seed at the All England Club, hasn't dropped a set so far in the tournament. Against de Minaur, he faced only three break points and saved them all while producing nearly twice as many winners, 30-17.
This is Nadal's eighth trip to the round of 16 at Wimbledon, where he has won two of his 17 Grand Slam titles. A year ago, the Spaniard lost at that stage.
He and Roger Federer, who is No. 2 in the world but the top seed here, have swapped the No. 1 ranking a half-dozen times this season, the most since there were eight changes in 1999.
"Of course, I prefer to be No. 1 than No. 2, no doubt about this," Nadal said. "I really don't come here to hold No. 1. I just came here to try to do the best tournament possible. ... The most important thing for me is be healthy, be happy playing tennis. Both things are very close."
Asked whom he would prefer to face if he reached the final, Nadal said he'd prefer anybody but Federer.
"If I am in the final, I prefer to face an easier opponent," a smiling Nadal said. "I am not stupid."
Ernests Gulbis of Latvia became the first male qualifier in six years to make the fourth round at Wimbledon after coming from a set down to beat fourth-seeded Alexander Zverev of Germany 7-6 (2), 4-6, 7-5, 6-3, 6-0.
Gulbis' ranking has fallen to 138th after struggling for form in the past few years, having reached No. 10 in 2014. But he looked back to his old self in defeating one of tennis' top young talents, dominating the final set on No. 1 Court.
He is the first qualifier to reach the men's fourth round since Brian Baker in 2012.
Novak Djokovic also reached the fourth round with a 4-6, 6-3, 6-2, 6-4 win over home favorite Kyle Edmund.
Djokovic didn't let a bad call on a crucial point get the better of him. He was robbed of a break at 3-3 in the fourth set when the ball bounced twice before Edmund managed to return it over the net at 15-40. Djokovic complained to the chair umpire, but the call stood -- even though TV replays showed Edmund's shot actually landed wide.
Edmund ended up holding serve, but Djokovic broke at his next opportunity to make sure there will be no British players in the second week of the tournament.
Edmund was the top British man in the draw in Andy Murray's absence and beat Djokovic on clay in Madrid this year. But his exit means all 12 British players -- four men and eight women -- have been knocked out.
This is the 44th time Djokovic has reached the fourth round at a Grand Slam, surpassing Jimmy Connors in second place.
Frances Tiafoe let a two-set lead slip as he failed to become the youngest American male since 1990 to reach the fourth round at Wimbledon.
The 20-year-old Tiafoe lost to Karen Khachanov of Russia 4-6, 4-6, 7-6 (3), 6-2, 6-1 after struggling through the last two sets. He was trying to become the youngest American in the round of 16 at the All England Club since Michael Chang 28 years ago.
Tiafoe blamed stomach problems for derailing his match. He said he started feeling badly late in the third set.
"Body just didn't feel right," Tiafoe said.
The loss "is definitely going to hurt," he added, because for the first two sets Khachanov "had no chance."
"Just felt it was completely in my hands," Tiafoe said.
As for the two last lopsided sets, Tiafoe said he "gave everything I was able to do."
"It's the third round of Wimbledon," he said. "I would never throw the match."
At 22, Khachanov is the youngest Russian in the fourth round since Mikhail Youzhny in 2002.
Fifth-seeded Juan Martin del Potro and former finalist Milos Raonic also advanced, as did Kei Nishikori.
Del Potro overcame a hot-tempered display from Benoit Paire to reach the second week at Wimbledon, winning their third-round match 6-4, 7-6 (4), 6-3.
Paire slammed his racket and shouted loudly at the chair umpire and himself after losing the second set, and his antics had del Potro shaking his head in return. The Argentine, who had crossed the net to help Paire back on his feet after a fall during the second set, still took a 3-0 lead in the third before the Frenchman fought back to level it at 3-3.
The match was then interrupted for about 10 minutes with Paire facing another break point at 4-3 while medical staff treated a spectator who had fainted in the heat. When play resumed, Paire saved that point with a service winner but was eventually broken when he netted a backhand, allowing del Potro to serve out the match.
For del Potro, it was his 87th career Grand Slam victory, breaking a tie with David Nalbandian for second most by an Argentinian-born player in the Open Era (Guillermo Vilas, 139).
Raonic reached Wimbledon's fourth round for the third consecutive year, finishing off a 7-6 (5), 4-6, 7-5, 6-2 victory over 171st-ranked qualifier Dennis Novak of Austria in a match suspended because of fading light the night before.
Play was halted with Novak about to serve while trailing 6-5 in the third set, and Raonic got off to a perfect start when they resumed Saturday by breaking to take that set.
The 13th-seeded Canadian was the runner-up at the All England Club in 2016, losing to Andy Murray in the final. Raonic lost to eventual champion Roger Federer in last year's quarterfinals.
On Monday, Raonic will face 103rd-ranked Mackenzie McDonald of the United States for a quarterfinal berth.
Nishikori equaled his best Wimbledon performance as he advanced to the fourth round by beating Nick Kyrgios 6-1, 7-6 (3), 6-4.
The 24th-seeded Nishikori of Japan won the first set in 16 minutes before seeing off an improved performance from his Australian opponent for the remainder of the match.
The 2014 US Open runner-up, Nishikori has twice previously made it through to the last 16 at the All England Club. He was defeated by Raonic in 2014 and retired hurt during the second set against Marin Cilic in 2016. He next faces Gulbis.
Nishikori and the 15th-seeded Kyrgios, a former Wimbledon quarterfinalist, began their match on No. 1 Court only after 7 p.m. local time, meaning light was fading toward the end of the 1½-hour match.
The Associated Press contributed to this report.