Roger Federer

Federer was given a thorough examination in his first meeting with the 19-year-old but despite Tiafoe's admirable effort, the Swiss great proved too strong to book his third-round spot and a possible meeting with Juan Martin del Potro if the Argentine can see off Robin Haase

Despite the gulf in experience between the players, Tiafoe underlined his status as one of the brightest talents in the game with a spirited display full of huge potential and winners off both wings.

Federer won 6-4 7-5 to register a fifth championship at the California tournament, to add to the Australian Open trophy that kick-started his year.

Seeded ninth, 36-year-old Federer again belied his years and beat his Swiss compatriot Wawrinka for the 15th consecutive time on a hard court.

The match began at breakneck speed, the hard court enabling both players to play aggressively. Wawrinka's power translated well, but not as well as Federer's guile.

Nadal was made to fight tooth and nail but showed glimpses of his best tennis, prevailing over 15th seed Dimitrov 6-3, 5-7, 7-6 (7-5), 6-7 (4-7), 6-4 in just short of five hours.

The Spaniard, who had an injury-ravaged 2016, needed three match points to see off a resilient Dimitrov and win through to Sunday evening's final against Federer.

"To qualify for the final in a match like this means a lot to me," Nadal said in a courtside interview.

The legends last met on a court playing some playing mini tennis with some juniors and discussed playing a charity match.

Instead they may square off in a grand slam decider that many — including themselves — felt was beyond them.

The last time the duo battled in the final at Melbourne Park was in 2009, which the Spanish bull won.

Federer, 35, is returning from six months out following knee surgery while Nadal, 30, had an injury-ravaged 2016.

"It might be, as far as history goes, the biggest match ever in Australian Open history — and maybe grand slam history," the former world number one said as the two tennis titans continued their march through the Melbourne Park draw.

"What's at stake there is beyond what pretty much what any player can comprehend.

"You could walk off that court with (numbers) one and two all-time on the grand slams list."I'd like to see it."

Playing only his third tour match since coming back from a knee injury, Federer was expected to be tested by the hard-hitting Czech but he sent the 10th seed packing after a 90-minute masterclass at a floodlit Rod Laver Arena.

The 35-year-old Swiss, seeded 17th, had shown rust in his earlier matches but was in spell-binding touch with 40 winners, wrapping up the match with an imperious cross-court backhand.

Federer will meet fifth seed Kei Nishikori for a place in the quarter-finals.

Federer, who has claimed four Australian Open titles himself, believes Kyrgios isn't experienced enough to go the full length.

"To win, he drops, in my humble opinion,'' Federer told Fairfax Media. 

''To do anything, yes, first week no problem, but to go all the way it's a long way, and he's never been into a semis before, so first he has to prove to the world and himself that he can make the semis.

"So for me to start talking about him winning the tournament, Lleyton [Hewitt] never did it, and he was two times world No.1 at the end of the year.

The world number one was reported to have been involved in a close shave with a truck pre-tournament but insisted wildcard Ward came closer to knocking him off on Monday.

"Yeah, actually just also recently they told me about that small article that went into papers. There is no truth to that," Djokovic said after opening his title defence with a 6-0, 7-6 (7-3), 6-4 win.

"Actually I did come few days in the beginning of the week before Wimbledon with my bicycle.

The 34-year-old world number three's appearance at Roland Garros had been in doubt after he missed the Madrid Open with back problems and suffered an early defeat at the Italian Open in the build-up to the claycourt major he won in 2009.

The last time the 17-times major champion was absent from one of the sport's four majors was at the 1999 US Open.

"I regret to announce that I have made the decision not to play in this year's French Open," father of four Federer said in a message posted on Facebook.