Novak Djokovic is back and the signs are he has repaired something far more significant than the elbow injury that kept him out for six months. He looks as if he's also fixed his mind.
The 30-year-old had suffered a bizarre year even before he walked away from Wimbledon following a quarter-final exit last summer, then disappeared to get his troublesome arm sorted.
Only once going beyond the last eight in five Grand Slams, he'd been knocked out in the second round in Australia, the tournament he had won a record six times. He split with his coach Boris Becker, then he employed Andre Agassi but fell under the spell of Spaniard Pepe Imaz who preached peace and love as the way to win tennis matches.
Imaz is still part of his camp, but the signs last night were that Djokovic, who built his reputation as one of the fiercest, never-say-die competitors on the circuit, is ready to go to war again. And if that's right at 7.87/1 to win his seventh title he looks rather good value.
In blistering, tortuous temperatures that touched an incredible 69 degrees celsius he spent the first set working Gael Monfils from one side of the court to the other, not bothering that he lost it 6-4.
Then he turned the heat up even more on an opponent who was broken in the sunshine and dropped only seven more games on the way to the third round.
Jim Courier on Aussie TV recalled Agassi used to do something similar. "We called him the Punisher because he'd try to get opponents to default through exhaustion. He achieved it four times."
It's a significant change in a man who seemed to have lost his way, but it seems this transformation began very quietly back in December as he put together his new coaching team in preparation for his comeback.
Agassi, who had begun working with him in France and at Wimbledon, stayed for the Grand Slams. Imaz stayed too, but maybe with a role more suited to helping him relax rather than being the main focus of his tennis tactics.
And added to the team was Radek Stepanek, who at the age of 39 had just hung up his own racquets after a decent playing career, with the job of working as Djokovic's day-to-day coach while Agassi jets in for the big days.
Growing up in the Czech Republic Stepanek idolised Ivan Lendl, and followed his lessons of dedication and professionalism. That's the attitude he's bringing back.
Now, in fairness, Djokovic has never needed too many lessons in those qualities, but it would appear he realised he needed somebody to keep reminding and prompting him. Becker had done that, and now Agassi and Stepanek together are rekindling the old ruthless approach.
Next up is Ramos Vinolas, a dangerous Spanish clay court player who is 24 in the world. He's the sort of opponent who against last year's "peace and love" model of Djokovic would have had a chance.
This time, though, it looks as if he'll be facing Novak the warrior. And that's something that none of those left in the Australian Open field will look forward to.