!Picby Pete Bodo

At this time last year, Novak Djokovic was on the cusp of an accomplishment that served as a catalyst for his brilliant 2011. He was about to lead Serbia to the Davis Cup title, much like Rafael Nadal is poised to lead Spain—or Juan Martin del Potro is about to lift Argentina—to the same year-ending triumph.

The emotional boost and confident enthusiasm Djokovic took into this year from that win should not be overlooked, nor should it be ignored that Djokovic will not have that form of rocket fuel in just a few weeks time in Australian, when he begins the quest to defend, well. . . everything.

It seems a good way to put his upcoming year into perspective, and not just because of what happened toward the end of 2010. It's also because of what happened at the end of 2011, in a way that has nothing to do with the season-ending tennis event, the Davis Cup final.

The intriguing and somewhat surprising element in the career year Djokovic just put together is how the wheels fell off after he won the last major of the season (and his third of 2011) at the U.S. Open. In some ways, that mid-September Grand Slam finale remains the end of what all but die-hard tennis fans tend to think of as the "tennis season." Yet the tour goes on and the tennis establishment (including the players) have worked overtime to extend the action and promote a final, year-end playoff. The problem for Djokovic is that when it came to that segment, he just plain ran out of steam. Or health. Or desire (a loss of appetite easily obscured by the very real injury issues Djokovic faced).

Djokovic still went 70-6 on the year for a .921 winning percentage—that .900 number being the baseline for "great" as opposed to merely terrific or excellent years. (See a pre-2011 Top 10 list here.) Percentage-wise, Djokovic tops the .906 mark Bjorn Borg hit in 1977 with a 76-8 record, and the Serb is just a shade behind Ivan Lendl's 1982 winning percentage of .922—on an iron-man mark of 106-9.

If you're wondering how Lendl was able to win so many matches, it was because there were two competing tours at the time (World Championship Tennis and the standard Grand Prix, the precursor to the ATP tour). Lendl, both durable and money-hungry, played them both. But what's most noteworthy is that despite all those wins, Lendl played just two majors in '82 and won neither. He lost in the fourth round at Roland Garros to Mats Wilander and in the U.S. Open final to Jimmy Connors.

In this discussion, it's more relevant that Lendl is the only man on the list to win more more than 100 matches in a given year, while Djokovic made the .900 club with fewer wins than any of his peers. Roger Federer, the only player who appears in the .900 club three times (with the third, fourth and eighth best-ever winning percentages), won four more matches (74) than Djokovic did this year in the "weakest" of his three .900-or-better years.

Of course, when you take into account that Djokovic retired in two matches, gave up a walkover in yet another (to Tsonga, at the Paris Masters), and seemed physically impaired (shoulder) in still another (loss to Nishikori, semis of Basel), his record looks that much more impressive. And Djokovic looks even better when you factor in his record at the majors.

We saw that Lendl didn't even win a major in one of his best years. In another (1985, good for sixth on the list at .930 on 80-6) he won only one. And when John McEnroe posted the all-time best winning percemtage of .965 (on 82-3) in 1984, he won only two majors (Wimbledon and U.S. Open). He skipped the Australian Open, as did many top players over the years in that era, and he was runner-up at the French Open (losing to Lendl).

Jimmy Connors' second-best all-time-best winning percentage of .957 (on 89-4) in 1973 gets an enormous asterisk because he skipped Australia, lost his first match at the French Open, and couldn't get beyond the quarterfinals at the two other majors. More to the point, Connors avoided the elite WCT tour and fattened up that record on a rival albeit much smaller tour run by his manager, Bill Riordan. Connors may not have bagged a title in London or Paris in '73, but he emerged triumphant in Hampton, Virginia and Paramus, New Jersey. Whoop-dee-do!

In fact, there isn't a three-Slam man until the No. 4 position, and it's Federer (why am I not surprised?). In 2006, The Mighty Fed went 92-5 for .948—just a few ticks on the scale below his 2005 mark of .953, which remains third-best in the Open era. The fifth best was Connors' overpowering 1974, during which he won three majors (he was banned from the French Open because he insisted on taking advantage of the big World Team Tennis paydays). So the only members of the .900 club who won three majors during their qualifying year(s) were Connors, Federer, and Djokovic.

If you value the majors as much as I do, you may agree that the three best years were the ones in which those men did their most Grand Slam damage, and that Federer was one match better than Djokovic to claim the top spot (Federer lost in the 2006 Roland Garros final to you-know-who, while Djokovic lost int he 2011 French Open semifinals to you-know-who No. 2).

But when you look at how durable the other members of the .900 club were—physically, mentally and emotionally—you have to wonder what the future holds in store for Djokovic. In 1984, McEnroe went 13-1 after he won the U.S. Open (that solitary loss was in Davis Cup play) with two titles. In 1974, Connors went 20-1 with three titles after his triumph in New York. And in 1985, Lendl went 28-1 after he won the first of his many U.S. Open titles.

Right about now, some of you might be thinking that this is a different era, with different demands, greater pressures, and a higher general level of competition—all of which are subjective, maybe/maybe not judgments. After all, the overlapping Connors-Borg-McEnroe-Lendl years were easily the equal of the present Federer-Nadal-Djokovic-Murray era. Had the Australian Open been worth playing all those years since the early 1970s, those older players would have amassed far more hefty Grand Slam stats. But even if we accept that this era is more demanding, how do you explain Federer's fall of 2006? He went 22-0 with four titles, including the season-ending championships.

Djokovic's collapse (he went 6-4 after the U.S. Open) suggests that all bets are off for 2012. Even if he starts the year in perfect health, the notion that he's really transformed himself into a Lendl-like iron-man is shot. Sure, he may re-convince us, but the reset button has been hit, the fear factor may no longer be on his side. And don't think that Rafa, Roger and company aren't thinking and/or hoping that they may have weathered the Djokovic storm—leaving them free to contemplate payback.

But Djokovic can still take comfort in the fact that it's awfully hard to burn out a player on a roll. Following his remarkable 1974, Connors started the following year on another tear—he was 43-3 going into Wimbledon, and he was defaulted in New York in a final for one of those three losses. In his back-it-up year of 1986, Lendl was 26-0 before he lost his first match (to B. Becker, in Chicago). And Federer embarked on 2007 with 12 straight wins (including one that earned him the Australian Open title).

So for all the speculation about the pressure a .900 clubber may face the following season, the sampling suggests that the men pick up where they left off with relative ease—perhaps even with replenished enthusiasm and determination. This still begs the question, how will the dramatic tailing off by Djokovic in 2011 affect his future? It's not like he closed 2011 as powerfully as those aforementioned men did.

That, even more than "What can Novak Djokovic do for an encore?" (to which the only answer can be "not a danged thing") is the major question looming on the horizon for the new year.