More than ever, Wawrinka the biggest threat to Djokovic's reign

The resistance to Novak Djokovic's domination of men's tennis appears to have crumbled, with the other three members of tennis' Big Four (Roger Federer, Rafael Nadal, Andy Murray) either out of ideas or unfit to compete with the 28-year old world No. 1.

In reality, though, Djokovic's most dangerous opponent isn't even part of that celebrated trio. The player best equipped to halt the Djokovic juggernaut these days is Stan Wawrinka.

The reigning French Open champion, Wawrinka re-arranged his 2016 schedule in order to play in Dubai, where he's seeded No. 2 this week. Given that Dubai is one of top-seeded Djokovic's best tournaments (he's won it four times thus far) you have to wonder: What was Wawrinka thinking?

Officially, he was thinking that a change of scenery might do him good after eight years. As he told reporters when he arrived in Dubai, "I went to play Latin America on clay, [but] mentally, it's good to see new tournaments. I think I'll get good energy [from the] change [in] my schedule."

Unofficially, there may be more to it than that. Wawrinka lost first-round matches the two times he played Dubai (2007 and 2008), before he fled to comforting clay. In the interim, Wawrinka's hard-court game has improved immensely. So has his status in tennis, as well as his self-esteem. He may not be hunting Djokovic, but he's not shrinking from the challenge either.

Wawrinka has lived the past few years right on the margin separating the game's elite from the contenders and also-rans. Unlike, say, Tomas Berdych or Kei Nishikori, Wawrinka is a proven Grand Slam champ with two singles titles (Australian Open of 2014 and French Open 2015).

That puts Wawrinka in an entirely different category, even if, at age 30, it's too late for him to insert himself into the Big Four or to bend that concept into a Big Five. Wawrinka has always accepted that, and he knows none of it will matter if he can cement a reputation as Djokovic's nemesis.

Wawrinka appears committed to that mission, as evidenced by his decision to play Dubai and the work he put in after the Australian Open.

"I was happy with [these] quite fast conditions for an outdoor tournament," Wawrinka reported after his first practice session in Dubai. "I worked hard after the Australian Open at home, undertaking a lot of fitness and some tennis."

It's hard to overlook Djokovic's 19-4 head-to-head advantage against Wawrinka. But the Swiss has two wins in their last six meetings, going back to the start of 2014. Federer has a better recent record against Djokovic, but for this killing detail:

Djokovic has handled Federer with relative ease in five-set Grand Slam matches. Wawrinka, by contrast, has beaten Djokovic in two of their three most recent Grand Slam meetings, and even the one he lost (Australian Open semifinals, 2015) went the five-set distance.

"In Grand Slams, when I play [Djokovic], I always play my best tennis," Wawrinka said. "The power I have from the backhand, from the baseline, from the forehand, that makes me feel I have a game I can trust and go up to beat him."

Wawrinka's confidence traces back to their first completed Grand Slam clash, in the fourth round of the 2013 Australian Open. The match was an epic with Djokovic winning 12-10 in the fifth set. Wawrinka felt he learned a lot about himself, and about problem-solving, in that match. They were clearly lessons that have remained with him. As he said in the aftermath of that bitter experience:

"Especially I was dealing with myself all the five hours, trying to always find solution, trying to always fight against me and against him to stay with him," he said. "For sure I'm really sad. It's a big deception to lose that match. But I think there is more positive than negative."

Since then, Wawrinka has become quite adept at "finding solutions." It's as critical a part of his game as that explosive, picture-perfect one-handed backhand. That has helped transform him into a more lethal competitor, a guy with mental reserves as well as physical power.

Just as important, Djokovic knows Wawrinka feels inspired playing him at majors. And that can make a world of difference at critical moments when the salient question becomes: "Who's going to blink first?"

Granted, the head-to-head record is littered with one-sided wins by Djokovic. But nobody is going to remember those, and Wawrinka knows it. So what if Djokovic dominates the stats but Wawrinka wins an inordinate share of the big matches?

Wawrinka knows that it's all about those Grand Slam encounters. So does Djokovic. There have been six of those: Djokovic has won four, but just one of the past three.

Welcome to tennis' best kept secret rivalry.