He has remarkable agility. Pundits are blown away by his mobility. His whippet-lean body facilitates his flexibility. But when you come right down to it, the thing that makes Nick Kyrgios the most dangerous young tennis player on the planet is something that only calls upon those attributes in a limited way.
His most fearsome gift is his power. His ability to make a tennis ball explode off his racket, producing not just those stat-enhancing, eye-catching aces, but those down-and-dirty, critical service winners.
The 21-year-old Australian is ranked No. 16, but he has been corkscrewing through the rankings like a bottle rocket since he burst upon the scene at Wimbledon in 2014. He called upon his kinetic superiority once again in the fourth round of the Indian Wells Masters 1000 on Wednesday evening. He drilled right through No. 2 ranked Novak Djokovic -- often hailed as the best serve returner in the game -- in just 1 hour, 51 minutes to win 6-4, 7-6 (3).
It was Kyrgios' second win over Djokovic in the span of three weeks, and it added more voices to the growing choir singing, "Where have you gone, Novak Djokovic?" Barely eight months ago, Djokovic dominated the ATP World Tour and had even the most jaded skeptics wondering if he might accomplish something even the mighty Roger Federer had failed to achieve: complete the first calendar-year Grand Slam since Rod Laver did it for a second time in 1968.
It all went awry for Djokovic starting with his third-round loss to Sam Querrey at Wimbledon last year. His No. 1 ranking was gone by the end of 2016. His attempt to hit the reset the button has sputtered out. Although he won Doha at the start of the year, Djokovic has failed to reach the semifinals in three consecutive tournaments now, including the Australian Open.
Rumors about difficulties in Djokovic's personal life have hounded him since Wimbledon. He admitted that he had been dealing with private issues over the summer shortly before the US Open began but declined to elaborate.
"I think if there's any champion in the past you'd consider machine-like, it's been Novak," ESPN analyst Chris Evert said in a conference call Tuesday. "I think to be No. 1 you have to be 100 percent focused physically, mentally and emotionally, and sometimes life gets in the way, and there are distractions. I don't know what [the distractions] are, but I think that probably has affected him more so than the physical."
Brad Gilbert, also an ESPN commentator, added: "Djokovic dominated for so long, so many players just dreaded playing him, and then all of a sudden, since Wimbledon last year, you know, he hasn't played to the same level that we've seen from him, and that changes the attitude of the players going out playing against him."
Count Kyrgios among the players who no longer quake in their kicks at the sight of Djokovic.
But it's also true that a year ago, the threat Kyrgios represented was not as urgent. An opponent could reasonably count on Kyrgios to find creative ways to torpedo his chances, either through shot selection that might make Gael Monfils scratch his head or by becoming embroiled in some petty, but inevitably unprofessional, controversy. Kyrgios led with his chin, not that whiplash forehand.
Those times may be over, although with Kyrgios, you never really know.
"I just sit there and watch him and just marvel and his athleticism," Gilbert said of Kyrgios. "I can't believe for his size how well he can move, how explosive. He ticks all the boxes for me game-wise. But just there's sometimes more to winning Slams and being great than just that."
Gilbert said that while Kyrgios "gears up" for big matches, he often seems to have trouble rallying his motivation for early round matches on outside courts. The supercharged atmosphere at Grand Slam events may mitigate that, but not entirely. And the sense of occasion is counterbalanced by the sometimes stifling pressure to perform. That leaves Kyrgios with two obstacles to overcome: his own fluctuating motivations and his penchant for sparking controversy.
Kyrgios got off to a rough start this year, losing to No. 89 Andreas Seppi in the second round of the Australian Open. But the Aussie has played solid tennis since then. Just as significant, he hasn't put his foot in his mouth -- or planted his racket in the cranium of a linesman or spectator.
Kyrgios was suspended at the end of last year following a tanking controversy in Shanghai, effectively ending his year. As part of his punishment, he was obliged to meet with a sports psychologist. It may have helped Kyrgios come to grips with his famously ambivalent feelings about his profession. A comment that the mercurial native of sleepy Canberra, Australia, made after he knocked off fellow prodigy Alexander Zverev in the third round suggested that he's finding a more productive way to face the pressures he faces as a star whose notoriety has outrun his accomplishments.
"I don't go into that match thinking, 'I must win this,'" Kyrgios told reporters. "I don't add stupid pressure on myself. I'm only human. If I make a mistake, I make a mistake."
The pressure Wednesday night flowed in the other direction, from Kyrgios to Djokovic. The No. 2 seed had plenty of stress in his life already. The last thing he needed was having to play resurgent Juan Martin del Potro and ascendant Kyrgios in back-to-back matches in consecutive tournaments. Djokovic, who dabbles in quasi-spiritual matters, must be pondering the role of "karma" in his life these days.
But karma represents one kind of power, while Kyrgios' serve is another. He won 86 percent of his first-serve points -- 16 percentage points better than Djokovic. The Serb never saw a break point, and he didn't reach deuce until Kyrgios was serving at 4-5 in the second set. Kyrgios, meanwhile, juked and jived and smacked his way to five break points. That he was able to convert only one was one of the few encouraging signs for Djokovic.
Fans of Kyrgios' flash and dash needn't be alarmed; he hasn't been transformed into Jerzy Janowicz or Ivo Karlovic overnight. There was plenty of sizzle to go with his dazzling display of power. Among other things, he hit an airborne drop shot and wasted a good opportunity by going for a 'tweener when he had other options. At one important point, Kyrgios smacked a blazing down-the-line backhand winner off a sharp crosscourt backhand. Djokovic just glared at the place the ball hit, shook his head and muttered.
It has been that kind of year thus far for Novak Djokovic.