The permutations were endless heading into the ATP World Tour Finals. The eight best players in the world took their final 2013 voyage (excluding Davis Cup) to battle one last time. Considering the quality of players, there weren't any gimmes in London. But, weirdly enough, if you had to guess how things would turn out before the tournament began, that's pretty much what happened.
And with hindsight in our corner, we present to you the eight things we already knew were going to happen in the season-ending championships.
1. Novak Djokovic is who we thought he was
The skinny heading into London: If the Fantastic Four, X-Men and Avengers were carefully cultured in a petri dish, they'd come out as a 6-foot-2 dark-haired Serbian tennis star. Djokovic has been nothing short of superhero status since losing the US Open final. He entered the World Tour Finals riding a 17-match winning streak. He might have lost his world No. 1 ranking to Nadal, but he never lost his fire. Djokovic is the only player on tour who reached all four Grand Slam semifinals this season. Plus, he was the defending champ in London. Obviously, he was going to snare another title.
The result: He left the United Kingdom with a 22-match win streak, another trophy and a lot of redemption by smashing Nadal in the final. He defended well and was equally aggressive poaching the net, winning 14 of 19 points there. He's the No. 2 on paper, but undoubtedly the favorite to win everything moving forward.
2. Rafael Nadal is who we thought he was
The skinny heading into London: We don't need to regale you with Rafa's ridiculous 2013 backstory anymore. We know you know it. Beyond all the titles and other accolades, though, was a player who steadfastly wanted to manipulate his game to win on hard courts. So along came Indian Wells. Check. Montreal. Check. Cincinnati. Check. New York. Big ol' check. Boy, it must really eat at Nadal to be pigeonholed as a hard-court specialist. The guy should really branch out. Anyway, it was an awesome season, but he fizzled, if just a little, after New York. All that said, how many players could legitimately stop him?
The result: Turns out just one. The superhero guy we talked about in the previous section. Nadal played great, though. He went undefeated in the round-robin stage and handled Federer without much sweat. If only he hadn't taken Djokovic's No. 1 ranking, perhaps the Serb would have been kinder in the final.
3. Roger Federer is who we thought he was
The skinny heading into London: The Slam King fell out of the top five for the first time in a decade. He won one garden-variety tournament leading up to Wimbledon and then suffered a shocking loss to Sergiy Stakhovsky in the second round at the All England Club. But even when Federer started slowly falling from his perch, he always had a way of making us believe everything was OK. This season was different, though. We weren't sure if the six-time year-end winner would even qualify. But after a few fallow months, he showed some punch in Paris, which, yes, made us believe he'd fare decently in London, especially given the quicker indoor hard courts.
The result: Naturally, Federer did fare well in London, making the semifinals with a sweet comeback win over Juan Martin del Potro in the final round-robin match. From there, it was date No. 32 with Nadal, who predictably bounced the Swiss in straight sets. Oh, and in other news, after that match, Federer said he's ready for a strong comeback in 2014. There he goes again, making us believe trophies aplenty are waiting for him.
4. Stanislas Wawrinka is who we thought he was
The skinny heading into London: Every once in a while someone aside from the usual suspects needs to stand up and be the man. Why not Stan? For one thing, his Swiss compatriot was flummoxing, foundering and falling down the rankings. Wawrinka was, by and large, the most impressive player we didn't think would be all that impressive this season. He played arguably the two best matches of the season -- a 12-10 fifth-set loss to Djokovic in the fourth round in Australia and another five-set loss to the same Serbian in the semifinals of the US Open. Wawrinka won 13 more matches this season than he had in any other year and reached his maiden year-ender. He was playing inspired ball. So why not a trip to the London semis?
The result: Why not indeed. Wawrinka advanced by going 2-1 in his group before (you guessed it), Djokovic upended him in the semis. But good for Stan. Swiss tennis needs some star power anyway.
5. Juan Martin del Potro is who we thought he was
The skinny heading into London: This Argentine is a beast. He was clocking some forehands in London bigger than John Isner's serve. When that happens, you might opt for a slo-mo replay, because if you blinked, you missed it. For the first time since del Potro underwent wrist surgery in 2010, he truly looked like the player who had won the US Open a few months earlier. And what better way to set the tone for 2014 than by outing Djokovic and Federer in the round robin?
The result: Sounds delicious on the surface. Del Potro looked like he had his final group match against Federer in hand, but the 6-foot-7 star was undone by Federer's defense in the final set, losing the match and his chance for the semifinals. Afterward, del Potro said he would start working harder on the mental and physical aspects of his game. Good plan.
6. Tomas Berdych is who we thought he was
The skinny heading into London: Right before the onset of the year-enders, my intrepid cohort, Kamakshi Tandon, broke down why each player could win the tournament. When she got to Berdych, she took a long, contemplative pause. How do I know this? Well, she wrote "long pause" before feigning a few lines of optimism on his chances. The thing with Berdych is that he has spectacular talent with equally spectacular inconsistency. He was once a Wimbledon finalist. Of course, last season he fell in the first round. We could go on and on -- and on. But the bottom line is that you'd better have a whole lot of house money if you're placing any bets on Berdych.
The result: He lost to a rebuilt Wawrinka in his opener, overpowered Ferrer in his second match and played Nadal tough in a three-set, albeit meaningless, match. It's safe to say Berdych lived up to his fairly low expectations -- just as we thought he would.
7. David Ferrer is who we thought he was
The skinny heading into London: It's so easy to want to call Ferrer a scrappy dude, but that's not fair. The guys can outright play on every surface. Aside from Djokovic, he's the only player who reached the quarterfinals in each major this season. The problem, of course, is that his scrappiness (sorry!) catches up to him when business week begins. So as much as Ferrer deserved to be in the World Tour Finals, chances were he wasn't going to be able to wrest the momentum from the big boys with only an irrepressible mindset.
The result: Ouch. Ferrer went 0-3 and won only a single set, finishing dead last in Group A. He played well against Wawrinka in his final group match before fading in the third set. For Ferrer, it was another solid season but without the glitter and glamor.
8. Richard Gasquet is who we thought he was
The skinny heading into London: Essentially, we could copy and paste the talent-rich underperforming Berdych blurb here. Gasquet is a fun player to watch. He boasts one of the best one-handed backhands in the game, but his issue is that he's often more of a highlight than a doer. Sometimes you just need to grind (see: Nadal, Rafa). Unfortunately for Gasquet, who reached the ATP World Tour Finals for the first time in six years, he was in a foreboding group with Djokovic, Federer and del Potro. What chance did he realistically have?
The result: None whatsoever. Gasquet took a set from delpo in the opener but lost in three. Federer then handled him reasonably easily and Djokovic finished him off two days ago. Gasquet deserves his share of accolades for making the elite eight field. Any success at all would have been nothing more than gravy.