Rafael Nadal and Roger Federer matched each other stroke for stroke on their way to the third round of the Australian Open.
Unusually for the two biggest stars in tennis, they found themselves playing at exactly the same time, on Rod Laver and Hisense Arena.
And, after starting their matches together, they also finished them within a couple of minutes of each other, both securing straight-sets wins.
Top seed Nadal faced the lowest-ranked player in the draw, 17-year-old Thanasi Kokkinakis, the world number 570.
The Australian gave a very good account of himself but, not surprisingly, found Nadal too tough, the Spaniard winning 6-2 6-4 6-2.
Federer raced through the first two sets against Slovenian Blaz Kavcic but was given a tougher test in the third before coming through 6-2 6-1 7-6 (7/4).
Remarkably, it was the first match Federer had played away from Rod Laver Arena, Melbourne Park's centre court, for 10 years.
The Swiss joked he headed out early to make sure he did not get lost, but said: "It was nice, I enjoyed it.
"It's not really different to Rod Laver Arena. The dimensions feel the same. I don't feel like you need to make an adjustment. The crowds were really nice. It was a great atmosphere over there. I was happy playing there.
"It was a good first two sets I thought. I played really aggressively and it worked out. In the third set I think he was more consistent. He served better. In the process, it got closer. I'm happy I got it done in three."
The extreme heat policy was in operation while Federer and Nadal were playing after temperatures peaked at 43.4C.
That meant play was suspended on the uncovered courts, with Federer revealing he was not allowed to practise outdoors.
Nadal was more than happy to play indoors and was very impressed with his young opponent.
He said: "Even if that's his ranking, when you are playing against a young player, you never have that feeling. He was able to win the first round against a tough opponent like (Igor) Sijsling. That's not the real ranking on him.
"He played juniors, made two finals of grand slams last year, so he has a great future. He has the right level to try to be on the tour very soon. So he just has to keep working and that will happen."
It has been a talking point and a concern for the men's game that young players have found it so difficult to break through at the top.
There are signs now that a new generation is emerging, and Nadal said: "It's normal that new players are coming, new generations are arriving. That's happened in all the parts of the history of our sport.
"It's strange for the last few years that it didn't happen, so that's something really normal that should happen and probably will happen and that's good for the game."
It was an ideal lesson for Kokkinakis to see how far he still has to go, and he said: "Physically I think is probably the biggest thing that needs to improve. Just physically he's a beast. I've obviously got a way to go to get that strong and fit."
The teenager was also inspired by Nadal's praise, saying: "He's a legend of the game. For him to say that is a real big plus for me. I know I need to keep working. I have a lot of development to do. It's only just the beginning."
Tenth seed Jo-Wilfried Tsonga is a potential fourth-round opponent for Federer and he was in fine form in a 7-6 (8/6) 6-4 6-4 win over Thomaz Bellucci.
Japan's Kei Nishikori, the 16th seed, raced through against qualifier Dusan Lajovic, while Donald Young upset Lleyton Hewitt's conqueror Andreas Seppi in five sets.
Young, once the great hope of American tennis, is through to the third round of a grand slam for the first time since the US Open in 2011.
Meanwhile, eighth seed Stanislas Wawrinka was handed a place in the fourth round after opponent Vasek Pospisil withdrew ahead of their scheduled match on Friday with a back injury.
Spain's Roberto Bautista Agut caused the upset of the tournament so far with a five-set victory over fifth seed Juan Martin del Potro to reach the third round of a grand slam for the first time.
The Argentinian had been tipped as a dark horse for the title and was expected to meet Rafael Nadal in the quarter-finals.
But Bautista Agut, the world number 62, came from two sets to one down to triumph 4-6 6-3 5-7 6-4 7-5 as the clock ticked past 1am.
It was Del Potro's second straight defeat in the second round of a grand slam after losing to Lleyton Hewitt in five sets at the US Open.
Del Potro said: "I think he played a great match for the four hours. It's tough when someone plays at a very high level for four hours, tough to beat the opponent.
"I was close. But at every moment that I had a chance, he played an unbelievable shot.
"I think sometimes the favourites lose very early in a grand slam, like Federer at Wimbledon or Rafa, and then other ones at the US Open. Here it's my turn to get out very early in the tournament.
"But the season just started. I will try to be positive for the rest of the year."
It was not the latest finish of the night, that honour went to Benoit Paire and Nick Kyrgios.
Eighteen-year-old Australian Kyrgios had led by two sets on an ecstatic Margaret Court Arena but was undone by cramp as Frenchman Paire triumphed in five sets.
There was another five-set win, meanwhile, for Paire's remarkable countryman Gilles Simon.
The 18th seed had been on crutches on Friday after twisting his ankle in an exhibition match but, after defeating Daniel Brands 16-14 in the fifth set in round one, he fought back from two sets to one down to beat Marin Cilic.
Gael Monfils will play Nadal in what is sure to be a crowd-pleasing third-round tie after beating American Jack Sock, while there were also wins for Grigor Dimitrov, Milos Raonic and Feliciano Lopez.
Defending champion Novak Djokovic headlines the night session on Friday against Uzbek Denis Istomin, while third seed David Ferrer meets dangerous Frenchman Jeremy Chardy.