Things are about to get tough for Roger Federer at the Australian Open.
The Swiss has cruised through three rounds, but now faces having to beat Jo-Wilfried Tsonga, Andy Murray, Rafael Nadal and Novak Djokovic if he is to lift the trophy.
Federer arrived in Melbourne radiating positivity, declaring himself free of the back problems that contributed to his 2013 struggles and happy with his new racquet.
Victories over James Duckworth, Blaz Kavcic and, on Saturday, Teymuraz Gabashvili have told little about his prospects of being a grand slam force once again.
Monday's clash against 10th seed Tsonga should certainly change that, with the Frenchman also yet to drop a set.
Federer and Tsonga have met 13 times before, with the Swiss winning nine of them, but Tsonga has prevailed twice at grand slams.
When they played in the quarter-finals here last year, Federer won in five sets.
The sixth seed said: "This is clearly a tough draw I have had, especially looking forward now. But it's important for me that I keep playing well and I don't go crazy about who I play now.
"I'm happy that from my side I'm winning my matches in straight sets. It's been different conditions every match. So it's just good to get through and get a good feel out there."
If the jury is still out on Federer, who won 6-2 6-2 6-3, Rafael Nadal sent a warning to his title rivals with a clinical dismantling of Gael Monfils.
The flashy Frenchman simply could not cope with Nadal's consistent excellence and the world number one ran out a 6-1 6-2 6-3 winner.
Nadal, of course, will not be getting carried away, the top seed saying: "I think I played a great match. I'm very happy the way that I played against a very tough opponent like Gael.
"That makes the level that I played tonight better. But that's it. Just one very good day. That makes me feel confident, but I am in the fourth round. That's all."
Next up for Nadal is Japan's Kei Nishikori, who won 17 of the last 18 games in beating Donald Young 7-5 6-1 6-0.
The defeat of Young, who was struggling with a shoulder injury, means the USA once again has no men in the last 16 of a grand slam.
Grigor Dimitrov served notice that his time may finally be coming as victory over Milos Raonic took him through to the fourth round of a slam for the first time.
The Bulgarian has been tipped for stardom since his junior days, but has struggled to develop the physical attributes needed at the top level of tennis these days.
Since linking up with Australian coach Roger Rasheed last season, however, he appears to have stepped up a level.
Dimitrov, 22, won his first ATP Tour title in Stockholm in October and headed to Melbourne at a career-high ranking of 22nd.
It was very much a meeting of the next generation against 23-year-old Raonic, ranked 11th, but it was Dimitrov who proved the more consistent in a 6-3 3-6 6-4 7-6 (12/10) victory.
Dimitrov said: "I'm definitely satisfied that I have gone through that match. I think that's not going to be the last time that I play against Milos.
"I think it's a great stepping stone for me to get into that second week that I keep talking about. But I have practised a lot. I have done a lot of homework. So, to me, in a way it's a bit expected."
Dimitrov admitted the expectations of him have been difficult to live with, saying: "They play in my head sometimes.
"It's not easy, obviously. Of course everyone would talk and everyone would say whatever. But the one thing is that I know what I believe in and I know what I'm doing."
Spain's Roberto Bautista-Agut followed up his upset win over fifth seed Juan Martin del Potro with a hugely impressive 6-2 6-1 6-4 victory against 27th seed Benoit Paire and plays Dimitrov next.
France's Stephane Robert, meanwhile, won the battle of the lucky losers against Martin Klizan 6-0 7-6 (7/2) 6-4.
The world number 119 is the lowest-ranked player left in the draw and the first lucky loser ever to reach the fourth round in Melbourne.
Defending champion Novak Djokovic is likely to face his first test on Sunday against talented Italian Fabio Fognini, while third seed David Ferrer plays German Florian Mayer.