When the Australian Open begins in Melbourne next week, tennis fans should brace themselves for the impossible: Novak Djokovic, the dominant No. 1 player in the world, might be better than ever.

Djokovic had one of the finest seasons in history in 2015. He won three Grand Slam titles and lost in the final of the fourth. He won 11 titles overall. He reached 15 consecutive finals. He ripped top-10 opponents to bits and pieces, compiling a 31-5 record against them. He became the second man ever to beat Rafael Nadal at the French Open. If not for an inspired Stan Wawrinka, who beat Djokovic at the French Open, Djokovic would have become the first man since Rod Laver in 1969 to win all four Grand Slam singles titles in a season.

Can the 28-year-old Djokovic possibly do better this year? Chances are slim, because there are always injuries, upsets and fluky performances in tennis. The sport just isn’t as easy as Djokovic makes it look. Yet the 2016 season is only a few weeks old and Djokovic is already making people wonder. In Doha last week, he won his first title of the year without dropping a set and beat two more top-10 opponents, including long-time rival Nadal in the final.

Djokovic didn’t just beat Nadal. He destroyed him by a score of 6-1, 6-2. Djokovic hit 30 winners to Nadal’s nine, never lost his serve and showed nice touch at the net, where he hit a few lunging volleys. Djokovic even clobbered overheads, the one shot in his arsenal that has (occasionally) looked awkward in his time at the top. For the first time in his career, Djokovic now has a winning record against Nadal in their rivalry, 24-23. He has won their last five meetings, all in straight sets.

“It did feel as close to perfection as it can get,” Djokovic said after the Doha victory. “There are those days when you see a tennis ball as a watermelon, and I guess this was that kind of day.”

Nadal had a weak season, by his standards, in 2015, but he’s still relentless, athletic, and tireless—a man who doesn’t take a lot of drubbings. He also played much better at the end of 2015 and says he feels good about his game headed into Australia. Yet against Djokovic, Nadal was rarely in control of a point.

“I played against a player who did everything perfect,” Nadal said. “Since I know this sport I never saw somebody playing at this level.”

Brad Gilbert, an ESPN commentator and the former coach of Andre Agassi, gushed about Djokovic’s performance.

“He is as complete of a tennis player as I’ve ever seen,” Gilbert said. “The biggest change in the last two years, the reason why I think he’s become almost invincible, is how much more controlled offense he’s played.”

Djokovic’s baseline attack has become more difficult to read. In the Doha final, Nadal several times hesitated as he tried to anticipate where Djokovic would hit the ball. Crosscourt? Down the line? Deep to the middle? A short angle? Djokovic kept hitting his spots until he caught Nadal leaning, and then he hit a winner. It looked like Djokovic was downloading Nadal’s mind in real time. Nadal’s lefty forehand, one of the best the sport has ever seen, had little impact on Djokovic’s two-handed backhand in crosscourt rallies.

“His backhand is scripted from God,” Gilbert said.

Novak Djokovic takes part in a practice session ahead of the Australian Open. Photo: paul crock/Agence France-Presse/Getty Images

As close to perfect as Djokovic is playing, invincible is a risky word in tennis. One tweaked ankle or badly timed illness, like the one that left Djokovic looking pale just before the start of last year’s Australian Open, can lead to defeat. Besides Nadal, there is also Roger Federer, Andy Murray and the future, players like Milos Raonic, Nick Kyrgios and Borna Coric, who don’t seem like threats to Djokovic just yet but might in a few months.

Runs like the one Djokovic is on tend to make everyone forget that tennis can change quickly. Federer used to dominate like this, and seemed likely to win at least 20 Grand Slam singles titles in his career. And then along came Nadal, followed by Djokovic. Federer remains one of the game’s best at age 34—he begins this season ranked third, behind Djokovic and Murray—but he has been stuck at 17 major titles since the summer of 2012 (Nadal has 14 and Djokovic has 10).

Right now, Djokovic looks like he should never lose a tournament, Grand Slam or otherwise. He has looked that way for a while, but no one can keep up that pace indefinitely.

“Nobody is invincible,” Djokovic said in Doha. “I know that it can’t go forever, but I’m not thinking too much ahead of myself. I don’t try to make any kind of predictions.”