2014 ATP World Tour Finals: Burning Questions for the Contenders in London

Day one of the 2014 ATP World Tour Finals saw the home favourite crash to a straight-sets defeat. The time is perfect, then, to ponder some of the burning questions for the contenders in London.

Novak Djokovic is seeking to win the season finale in London for the third consecutive year. His challenge, though, is slightly clearer than some of the other finalists.

Andy Murray has come through a painstaking month-and-a-half to take his place in a group consisting of Roger Federer, Milos Raonic and Kei Nishikori. An opening defeat to Nishikori raises more questions than the Scot would have anticipated this early in the tournament.

The Bryan Brothers' prolific status in doubles tennis needs little corroborating, but a win in London would crown them season-ending victors for the first time since 2009.

The following slides will analyse the most significant questions ahead of a week of tennis at its most demanding. 

How Does Marin Cilic Follow Up His Grand Slam?

Ivan Sekretarev/Associated Press

The last time the eyes of the world were fixed on Marin Cilic he won his first Grand Slam. What are the chances he will go all the way again?

Events at the Arthur Ashe Stadium crowned perhaps the most unlikely of the major victors this year. In London, he will likely fall under the radar again.

Nobody expected Cilic to beat Roger Federer in the semi-finals and they certainly won't expect him to halt Novak Djokovic's runaway train in the round-robin stage.

Victory in the Kremlin Cup in Moscow, however, makes the Croatian one of two players to arrive at London on the back of a title. No prizes for guessing the other.

Any confidence he can utilise from beating a modest field in Russia should be capitalised on, particularly against Djokovic. 

Ian Chadband wrote for Reuters that it is almost "as if he has a target on his back" following his win at the U.S. Open.

However much opponents have been playing a more adventurous game against Cilic post-U.S. Open, Djokovic will, as is the norm, be the one to beat in London.

Perhaps, then, for the first time since New York, Cilic will be the one taking aim.

Will the Bryans Find the Winning Formula?

Michel Euler/Associated Press

In any ordinary tournament this would be a redundant question.

The Californian born Bryan brothers have won nine titles this season, including the U.S. Open.

Add to that six Masters 1000 events and the siblings synonymous with doubles tennis would look certainties if such a record was possessed by an individual.

The issue at hand is that they haven't won the ATP Finals since 2009, despite being in the final on two other occasions since they won the tournament back-to-back in 2003 and 2004.

In 2009, they won six tournaments plus London, yet last season they won 11 times but were beaten in the final by the Spanish duo of David Marrero and Fernando Verdasco.

Peter Bodo wrote for Tennis.com, "The biggest threat to the Bryans, on form, is the second-seeded team of [Daniel] Nestor and [Nenad] Zimonjic."

The pair have won the season-ending title twice before but lost to Ivan Dodig and Marcelo Melo in straight sets on Sunday.

When the Bryans lost Wimbledon to debutant pairing Jack Sock and Vasek Pospisil this year, they hit back by beating the North Americans in the final at Cincinnati.

They must find similar reserves to respond to their World Tour Finals drought. It's been five years coming.

Which Stan Wawrinka Will Turn Up?

Dean Mouhtaropoulos/Getty Images

Stan Wawrinka knows the score. His three Group A opponents have all won trophies since he last claimed a title. 

In Wawrinka's defense, the three tournaments he won this year included the Australian Open final against Rafa Nadal and the Monte Carlo Masters against Roger Federer. Hardly a rough season.

Perhaps just rough around the edges instead. The Swiss hasn't advanced past the round of 16 in his last four tournaments, losing to 103-ranked Tatsuma Ito in Tokyo. 

Yet he reached the quarter-finals at both Wimbledon and the U.S. Open, losing on both occasions to the tournaments' beaten finalists. 

Perhaps, then, another prominent tournament can work in Wawrinka's favour. Tomas Berdych is first up for him on Monday and represents an opportunity to lay down an early marker.

Wawrinka said of winning his first Grand Slam, via atpworldtour.com,: "You need to find a way to adapt, find a way to feel good and play well in all the tournaments."

Pressure? Self-imposed expectations? He wouldn't be the first tennis player to suffer from those. Next year will be about whether he uses them to his advantage or succumbs.

This week will be an early indication. 

How Much Does Andy Murray Have Left to Give?

Kirsty Wigglesworth/Associated Press

Most would cite the travelling or fatigue endured over the past month-and-a-half. Some would even stretch to complaining about the dance music that punctuated every break. 

Andy Murray, though, will accept that the better man won and that he must start again.

Tuesday will be a chance to make amends for his 6-4 6-4 defeat to Kei Nishikori in London.

Murray was second best against Nishikori, with the No. 5 ranked player calling on a range of perfectly executed shots to subdue the O2 Arena.

Three double-handed backhands out of Murray's reach and a terrific passing shot were mixed with a number of thunderous forehands. Murray began to find some momentum at 4-1 down in the second set, hauling himself to 4-4.

However, Nishikori held out to earn a deserved victory. Murray was never in control of a match that stumbled along before Nishikori unleashed his devilish forehand.

Murray couldn't handle it and paid the price. Of course, there were moments of sloppiness from last year's Wimbledon victor. He required three attempts to finally execute a simple drop shot, but Murray was outplayed from start to finish.

Raonic and Federer are next up, with Murray needing to recreate the resolve shown over the last six weeks to claw his way back into contention.