LONDON: The 'Big Three' of Roger Federer, Rafa Nadal and Novak Djokovic head into the second week of Wimbledon carrying the flag for the men's game after a number of young upstarts failed to live up to their potential on the grandest stage.

The trio, with 14 Wimbledon titles between them, have been in blistering form while players such as Alexander Zverev and Stefanos Tsitsipas -- younger men touted to end their hegemony at the majors -- went out with a whimper.

Having dropped only one set each in their three rounds so far, the trio seem a safe bet to advance when they face fourth-round rivals who have never before made it to this stage at the All England Club.

Defending champion Djokovic, who endured a hurricane against Hubert Hurkacz before winning in four sets, takes on Frenchman Ugo Humbert for the first time in his career.

"I've seen him in Roland Garros. I've seen him last year (at the) US Open... big serve, very explosive, very dynamic player," said Djokovic, who is seeking a fifth Wimbledon title.

"He's tall, has a big game from the back of the court, flat backhand, very solid. He can play anything really, he's an all-around player."

Eight-times winner Federer, who sealed his 350th Grand Slam match win when he dispatched France's Lucas Pouille on Saturday, has barely been tested so far barring his opening clash against Lloyd Harris where the Swiss rallied from a set down to win.

The 37-year-old meets 17th seed Matteo Berrettini who has claimed two titles this season, including one on grass in Stuttgart, and Federer expects a tough challenge.

"I don't know him well so that makes it a bit more tricky," Federer, who warmed up for the tournament with his 10th Halle Open title, said.

"I saw him play in Halle, saw his run in Stuttgart. Now he's backing it up here. That's not easy, especially when you're newer on the tour."

Third seed Nadal, who has repeatedly expressed his displeasure about the seedings and draw, is the only one among the three who would face unseeded players until the semi-finals, where he could take on Federer.

The Spaniard, who faced his biggest test so far against mercurial Australian Nick Kyrgios, is up against a familiar rival in Portugal's Joao Sousa.

"We know each other very well, practised plenty of times together. He's a player that when he's winning matches, he's a super dangerous opponent against everybody," Nadal said.