At age 28, top-ranked Novak Djokovic is at the zenith of his powers. He's fresh off a year in which he won three Grand Slam titles, bringing his total to 10 -- more than such stalwarts as Jimmy Connors, John McEnroe, Ivan Lendl and his own "supercoach," Boris Becker.
Last year Djokovic came within one match of sweeping all four Grand Slam singles titles -- a feat that even his WTA counterpart Serena Williams could not match in her own spectacular 2015.
Djokovic has assembled a loyal, low-key, brutally effective support team. He's a dutiful husband and doting dad. His personal life is not only in order, it's in complete harmony with his professional one.
Last year Djokovic's principal rivals were unable to contain him. Rafael Nadal misplaced his game while Roger Federer floated like a butterfly and stung like a bee but never landed a deadly punch, as Djokovic increased his choke hold on the ATP game.
Looking ahead to 2016, the question occurs: Where does he go from here? What do you do for an encore after a year in which you all but ran the table, compiling a record of 82-6 with 11 titles?
You do the hardest thing, which is more of the same. And then some.
"Grand Slams and Olympic Games are the priority of the season, but it's a long season, so I can't really predict what's going to happen or guarantee if I am going to win any of the Grand Slams or all four," Djokovic told reporters shortly after he arrived in Qatar to play the ATP Doha event this week. "Of course I am going to try to win every tournament and every Grand Slam that I play on -- that's kind of the mindset that I have."
That's the appropriate mindset, yet even Djokovic doesn't really know what his most basic, elemental attitude will be once the balls start flying with serious intent. And that's the tricky part. A number of great players have hit a wall and abruptly stopped winning major titles well before the realities of age and physical wear and tear became factors -- often taking us by complete surprise.
Bjorn Borg famously walked away from the game as an 11-time Grand Slam champ, burned out at the age of 25.
Granted, Borg was an extreme case. His rival McEnroe played until he was 33, but Borg was done as a Grand Slam singles champ by age 25 at the end of 1984.
Not to get us paranoid or anything, but that was a year during which McEnroe gorged much like Djokovic did in 2015; Mac went 82-3 with 13 titles, still the best single-season winning percentage of the Open era.
McEnroe won seven majors (he often skipped the Australian Open), as did Mats Wilander -- another great player whose run as a Grand Slam champ was surprisingly short-lived. Wilander was 24 in 1988, the year he won three majors (he lost only at Wimbledon) and finally secured the No. 1 ranking. But he quickly spiraled down and out of the game.
Stefan Edberg and Becker both won six majors. But Edberg was done winning the big ones at 26, while Becker did almost all of his damage before he turned 24. He did, however, craft a resurgence that paid off with a final singles title when he was 28.
Is it possible Djokovic has spent himself, after having logged two of the greatest years on record (2011 and 2015)?
It's unlikely. If you look at the players whose reign as Grand Slam champs were compressed, only Edberg was reconciled to his role as a top player the way Djokovic has. McEnroe was a rebel, Wilander a free spirit; Becker was a discontented seeker, Borg a prodigy drowning in the quicksand of his own fame.
Djokovic is a rational, well-adjusted man who appears to cherish his place in the world, accepting it as a privilege rather than an entitlement -- or a burden. But just as important, he also has a few serendipitous, built-in circumstances and incentives that should provide him with any spark he might need as 2016 spools out.
You can start with Djokovic's relationship with the Australian Open.
Melbourne Park is usually Djokovic's launching pad. He's won the tournament four of the past five years. To fully appreciate what that means, remember that the one thing the top players all agree upon is that any year when you win a major is automatically a good year.
One reason Djokovic has borne the pressures of his position so well could be that in winning the Australian Open, he's frequently crossed the biggest item off a player's to-do list a mere month into the new year. This would be a particularly good year for him to repeat that pattern, given the twin tasks he faces within roughly 60 days of each other starting (with any luck) in early June.
If there was a silver lining for Djokovic when he lost last season's French Open final to Stan Wawrinka, it's that it left the Serb with a mission for 2016. Winning at Roland Garros remains the outstanding piece of unfinished business on Djokovic's résumé.
In fact, preparation for the French Open -- mental and emotional, if not technical and physical -- is likely to be the major underlying driver in all of Djokovic's activities long before it emerges as the main theme in tennis this spring.
However Djokovic's Parisian quest turns out, he also will have the Olympic Games to play in Rio de Janeiro less than two months (and one Wimbledon title defense) after Roland Garros.
Djokovic makes no secret of his patriotic feelings, but thus far he's won just one Olympic medal for Serbia -- a bronze in singles at the Beijing game in 2008. The tennis in Rio will be played on Djokovic-friendly hard courts but under an Andy Murray- and Roger Federer-friendly best-of-three format.
So the most surprising thing about Djokovic's 2015 is that he's still left himself plenty to do in 2016, and that's probably bad news for his rivals.