When one of the big four falters, there's another one around to pick up the slack. Last week's Shanghai Masters was a typical example.
With Andy Murray out after back surgery, Roger Federer continuing his slide and Rafael Nadal a little off his game, Novak Djokovic stepped forward to collect the crown and maintain the group's collective grip on the big titles.
Individually, however, the four are taking eminently divergent paths through this last part of the season.
He might no longer be No. 1, but for the first time since February, Djokovic is setting the pace and has won back-to-back titles in Beijing and Shanghai during the past two weeks.
While fending off a very game Juan Martin del Potro in the Shanghai final, Djokovic showed his ability to absorb and counter the Argentine's power by twisting, bending and throwing his body into all sorts of positions -- and that was just in the second game of the second set. And though the diving volley may be a rare sight these days, Djokovic attempted something even more innovative in the third set -- a diving groundstroke. Leaping into a forehand, he hit the court almost at full stretch.
As slim as his chances are, Djokovic's recent success has also allowed him to keep Nadal within sight in the contest for year-end No. 1. Coming in about 3,000 points back in the year to date, Djokovic has earned 1,500 points in the past two weeks, though Nadal's respectable performances during the same period mean he has cut his lead by only about half of that. After the US Open, Djokovic needed to go almost undefeated and hope Nadal underperformed to have a chance to end the season at No. 1. It won't be easy to keep that up during the upcoming Paris Masters and World Tour Finals, but so far, so good for Djokovic.
After a magnificent season, the Spaniard is once again struggling to finish the year strong. He did manage to reel in the No. 1 ranking by reaching the Beijing final, but ironically, lost his next match to Djokovic -- the player he had just taken the top spot from.
The quick courts and the ball in Shanghai last week were not to Nadal's liking to begin with, and del Potro's monster hitting at the beginning of their semifinals didn't help matters. The Argentine won in straight sets.
After going 22-0 on hard courts coming in, why the change? Since Nadal had explained his earlier success by saying simply "I just played well, I think," a similar answer would be that now he's just not playing as well. The effects of a memorable but wearying season may finally be starting to show.
Still, don't think he's not trying. Many players would have given up the struggle by the time del Potro was serving to go up a set and 5-3 in Saturday's semifinal, but Nadal was still battling. He won the first point of that game and pumped his fist like he had just won the match. It was the same against Fabio Fognini in the quarterfinals of Beijing a week earlier. Nadal fell on his fragile left knee and then fell behind 6-3, 3-0 but still fought back to win. The Slams may be over, but mailing it in just isn't in Nadal's vocabulary.
And though the losses continued his pattern of struggling during this part of the season, the way he has lost also bears attention. When unsettled and tired in past years, Nadal has often retreated and played safe. There was a little of that against both Djokovic and del Potro, but generally Nadal has stuck to a more aggressive mindset and kept using his newer weapons -- the forehand down the line, the biting backhand slice, the opportunistic moves to net.
After getting almost blown off the court by del Potro early on, Nadal went for more, later explaining that on the fast Shanghai surface, "The only chance to change the dynamic of the game was to hit hard, closer to the lines." The shots didn't find the court as often as they have at other times this year -- Nadal finished the match with 22 unforced errors to 15 winners -- but he was trying to do the right things.
It might be something to build on as he heads to the indoor events that have been such a challenge in the past. Nadal has never won the World Tour Finals at the end of the season, perhaps the most significant title still missing from his collection.
Where to begin? There's the parting of ways with coach Paul Annacone, which was announced a few days ago and is the clearest sign yet that there is some strife behind the scenes. There's third-round loss to Gael Monfils in Shanghai -- just the latest in a series of discouraging defeats. But this defeat came on the quick, lower-bouncing surface Federer typically enjoys. There's the abandoned racket experiment. Federer was playing with his normal painted stick in Shanghai, not the larger, blacked-out prototype he tried out after Wimbledon and said he might go back to later in the year. Then there's the unexpected Twitter rampage early last week, complete with hashtags, "chillaxes," and impromptu Q&As.
Most likely it goes back to the discouraging defeats (Twitteritis typically defies explanation), so the match against Monfils may be the place to start. It provided the latest opportunity to dissect Federer's form, but the signals were mixed. On one hand, Federer produced an error-prone performance, and despite sneaking out the second set, he let the momentum slip away quickly in the third. On the other, he was playing just his second match after a four-week break and did have some patches of impressive play.
It's not just hard for Federer observers to know what to make of his recent level. His opponents are confused, too. As Monfils explained, they're not sure what to expect going into the match.
"But when he's on the court, he's still Roger," Monfils said. "He can rip it from anywhere. He can do stuff that not many players can do. I think we still have fear when we play against him [but] then maybe helps a little bit because you know he had a couple [of] loss. So it's less fear, but still, you're not going, 'OK, I play Federer; it's easy draw.' No, definitely not."
Monfils, a former top-10 player who is still climbing back up the rankings after an injury, pointed to consistency as the main difference in Federer these days. "I think he miss a little bit more than he used to," he said. "Because he used to play aggressive and maybe miss a bit less. Maybe I took a bit advantage of this. I know he will try and go for his shot, but maybe he is a bit less confident."
A year ago, Federer was marking his 300th week as No. 1. Now he is not only No. 7 but sliding fast. Even the few notable results he has had this season -- the Australian Open semifinals, Rome final, French Open quarterfinal, Halle title -- all came in the first half of the year.
That also means he's facing a battle to qualify for the eight-player field at the year-end World Tour Finals, with four other players -- compatriot Stanislas Wawrinka, Jo-Wilfried Tsonga, Richard Gasquet and Milos Raonic -- also in close contention for the last three spots.
And as if there wasn't enough attention surrounding his struggles, the decision to stop working with Annacone will create yet another line of speculation about who, if anyone, might replace the well-respected American coach.
The Federer watch only gets more intense next week as he arrives for the tournament in his hometown of Basel, Switzerland, where he is sure to receive a warm, if anxious, welcome.
After undergoing back surgery, Murray announced last week he will not be taking part in the World Tour Finals. He will instead get in some light play at an exhibition event a few weeks later and get ready for the new season.
Despite the injury, this has been a good year for Murray. It will be most remembered for his drought-snapping Wimbledon victory, where he collected his second Grand Slam and Britain's first men's title since 1936. The Australian Open final and Miami title were his other biggest results, but back problems during the clay season and forgettable post-Wimbledon performances meant that the No. 1 rank remained out of reach.
Now, lack of play means Murray finds even his No. 3 ranking under threat from del Potro, and Murray will need to make a quick recovery if he is to defend his points as next season begins.
But after adding the Wimbledon trophy on his shelf, it's unlikely he's anything but satisfied with his overall record. His back may be painful, but his shoulders have had a huge weight lifted from them.