Power Rankings: Murray, Federer join Wimbledon defending champ in top 3

Welcome to SI Tennis Power Rankings – a new recurring feature on SI.com that goes beyond the regular ATP and WTA rankings to grade and rank the top 20 men's and women's players by more than just points earned on tour. While tournament results and quality of play are considered, SI Tennis’ Power Rankings also take into account those unquantifiable metrics that make the sport so compelling—everything from injuries and meltdowns to big upsets and recent title wins, as well as other subjective assessments. Each edition of SI Tennis Power Rankings is intended to capture a more seasonal and timely portrait of the current tennis rankings.

Check out the newest edition of SI Tennis Power Rankings below as the players gear up for Wimbledon 2015.

1. Novak Djokovic

Previous Power Ranking: 1

How long will the disappointment linger after failing to bring home his first French Open title? Djokovic scored big wins over Rafael Nadal and Andy Murray en route to the final only to run into a Stan Wawrinka in "Beast Mode" to take his only loss of the clay season and first since February. Now comes his title defense at Wimbledon.

2. ANDY MURRAY

Previous Power Ranking: 2

The Brit still hasn't lost to anyone other than Djokovic in nearly four months. Since February he is 31-0 against anyone other than the Serbian No. 1 and he took Djokovic to five sets in the French Open semifinals. His top form has continued on grass. He won his fourth Aegon Championships title last week and says he's playing better than when he won his first and only Wimbledon title in 2013. Is he due for another championship run at SW19? 

3.

He was blown off the court by Wawrinka in the French Open quarterfinals but rebounded last week in Halle, where he returned to his winning ways to capture his eighth title there and fourth of the season. He sits at No. 4 in the ATP Race to London rankings behind Djokovic, Murray and Wawrinka, but we're giving him a marginal boost now that the season turns to grass. 

4. STAN WAWRINKA

Previous Power Ranking: 8

There's no knowing which Wawrinka will show up during any given week—the one who is now 2-0 in Slam finals after winning the French Open or the one who struggled to in back-to-back matches for much of the 2015 season thus far. But he can beat anyone on any given day and though he's no grass court stalwart, he continues to show at 30 years old he's still got some surprises left.  

5. Tomas Berdych 

Previous Power Ranking: 5

His 2015 quarterfinal streak ended in Paris with a loss to Jo-Wilfried Tsonga in the Round of 16, but he started anew with a quarterfinal run in Halle last week. That level of consistency obviously keeps his ranking high, but we're still waiting for any sort of run that legitimizes him as a threat to the game's elite.  

6. KEI NISHIKORI

Previous Power Ranking: 3

After a strong clay season and a reasonably light draw at the French Open, Nishikori came out surprisingly flat against Tsonga in the quarterfinals and lost in five sets. It was his best performance ever in Paris but given the opportunity before him it felt like a disappointment. Last week he was forced to retire in the Halle semifinals with a calf injury. Will he be fully fit for Wimbledon? He has yet to make it past the Round of 16 there.

7. Rafael nadal

Previous Power Ranking: 6

Real talk: Nadal looked out of his league in a 7–5, 6–3, 6–1 loss to Djokovic in the French Open quarterfinals. Sure, he had his clay woes before the tournament—this was the first time he went into Paris without a European clay court title—but that was a shellacking. Now down to No. 10 in the rankings, Nadal has just a handful of points to defend for the rest of the season. 

8. DAVID FERRER

Previous Power Ranking: 7

He did well to grind his way to the French Open quarterfinals, where he lost to Murray. Now on his weakest surface, he's already taken an early loss to Marcos Baghdatis in the first round of Nottingham. 

9. MILOS RAONIC

Previous Power Ranking: 9

After skipping the French Open to undergo foot surgery, the Canadian played well in his first tournament back, advancing to the quarterfinals in Queen's. But is he in good enough shape to defend his semifinal run at Wimbledon last year? His serve gives him a chance any time he steps on court. 

10. GAEL MONFILS

Previous Power Ranking: 10

We hoped for more from La Monf when he took the court to play Federer for a spot in the French Open quarterfinals. In two grass tournaments so far he lost to Nadal in the Stuttgart semifinals and retired with injury to Andreas Seppi in the Halle quarterfinals. As usual, we have no idea what to expect from him at Wimbledon.

11. KEVIN ANDERSON

Previous Power Ranking: Out of Top 20

Prior to this year, Anderson had never made a grass court ATP final. He ended that drought last week by beating Wawrinka en route to making the Queen's final. Now up to a career-high No. 14, the South African is quietly having the best year of his career.  

12. GILLES SIMON

Previous Power Ranking: 16

He took care of business to make the Round of 16 at the French Open and his good play has continued on grass, where he beat Raonic in Queen's to make the semifinals before losing to Anderson. 

13. VIKTOR TROICKI

Previous Power Ranking: Out of Top 20

Another player who has historically struggled on grass, Troicki won seven of his nine matches on the green stuff in the last few weeks. He made his first ATP grass final in Stuttgart, beating Marin Cilic in the semifinals, and then the semifinals in Queen's, where he beat Cilic again and John Isner en route. Despite disappearing for much of the spring hard court and clay season, Troicki is now up to No. 15 in the ATP Race rankings.

14.

Previous Power Ranking: 13

Given how well he was playing on clay heading into Paris, his second round loss to Jeremy Chardy was disappointing. Now that we're on grass it's easy to fall into the trap of thinking Isner should be a threat given his big serve, but the American has never made it past the third round at Wimbledon or even made the semifinals of a grass court tournament outside of America. 

15. GRIGOR DIMITROV

Previous Power Ranking: 11

The struggles continue. He took a weak loss to Jack Sock in the first round of Paris and now, with a load of points to defend on grass, he lost in Queen's in the second round. His stock is sinking. Quickly.

16.

Previous Power Ranking: 12

The Frenchman came out of nowhere to make the French Open semifinals but now he's in doubt for Wimbledon after pulling out the lead-up tournaments with an abdominal injury. Tsonga has an uncanny ability of pulling off miracle runs only to completely disappear afterwards—see, e.g., 2014 Toronto—and for the sake of the sport we hope that's not happening here again. His explosive game creates tennis fans. 

17. NICK KYRGIOS

Previous Power Ranking: 14

Can Kyrgios return to the All England Club and rediscover the magic that took him to the quarterfinals last year? After a strong start, with wins over Federer and a run to his first ATP final, Kyrgios didn't do much for the remainder of the clay season. Now on grass, he complained of feeling "disengaged" in a loss to Wawrinka in Queen's and pulled out of Nottingham to take a break. He's also just split with his coach Todd Larkham just days before Wimbledon. 

18. DAVID GOFFIN

Previous Power Ranking: Out of Top 20

The Belgian lost in the third round to Chardy in Paris but started his grass season well, making the final in s'Hertogenbosch. 

19. IVO KARLOVIC 

Previous Power Ranking: Out of Top 20

It's the grass season. Karlovic always deserves a bump, especially when he just broke his own ace record by firing 45 in a win last week. This is not a man you want to see in the first week of Wimbledon.

20. Feliciano lopez

Previous Power Ranking: Out of Top 20

The Spaniard has not started his grass season well, taking losses to two big servers in Sam Groth and John Isner. But with his serve and volley style and lefty serve, he remains a dangerous opponent on the turf.