Seven burning questions ahead of the ATP World Tour Finals

As the final eight players prepare for the ATP World Tour Finals in London, Courtney Nguyen examines the seven questions that will determine who will finish the

As the final eight players prepare for the ATP World Tour Finals in London, Courtney Nguyen examines the seven questions that will determine who will finish the year-end championships raising the trophy at The O2. 

No. 1: Novak Djokovic or Roger Federer?

The year-end No. 1 ranking is in play in London and it will come down to No. 1 and two-time defending champion Djokovic and No. 2 and six-time champion Federer. With his run to the title in Bercy last week, the year-end top ranking is in Djokovic's hands. If he finishes Group A undefeated -- beating Stan Wawrinka, Tomas Berdych and Marin Cilic -- he'll finish the season at No. 1 for the third time in his career. He can also clinch if he makes the final with at least one round robin win. The Serb has held the No. 1 ranking since he defeated Federer in the Wimbledon final this summer.

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The fact that Federer is within shouting distance of the year-end No. 1 ranking is a remarkable accomplishment. After his poor 2013 season he fell to as low as No. 8 this year. But his season, which did not net a major title, has been all about consistency. Since losing the Wimbledon final he has lost just three matches, while winning 28, capturing three titles along the way.

With the race out of his own hands, Federer just needs to win his matches in London (and Davis Cup) to keep the pressure on Djokovic. If he goes winless in Group B, Djokovic can clinch in London with just one match win. The tricky thing for Federer is that his No. 1 prospects are tied to his performance in the Davis Cup final a week after London. ATP rankings points are meted out for a player's performance in the final, meaning Federer could earn up to 225 points if he wins two live singles rubbers and Switzerland goes on to win the title. Of course, all this is moot if Djokovic slams the door in London.

Can Stan Wawrinka get out of his funk?

Wawrinka has to get his game back online in time for the Davis Cup final. He was a semifinalist in his London debut last year and has been drawn into Group A this year. But since winning the Australian Open in January, Wawrinka has made it clear that his goal for the rest of the season was Davis Cup.

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Unlike Federer, Wawrinka has been staunchly committed to the international competition throughout his career and with Federer now on board, this may be the closest they'll come to finally winning the title.

But Wawrinka has yet to put the puzzle pieces back together after his breakthrough win. Inconsistency has plagued his season and he comes into London with questionable form and confidence. He's won just one match since the U.S. Open, taking three straight opening round losses. But if he can just get a couple of wins under his belt in London and qualify for the semifinals again -- entirely possible in his weaker group -- he'll go into Lille with a clearer head.

Does Andy Murray have enough left in the tank?

Titles Andy Murray has won in the city of London: 2012 Olympic gold medal, 2013 Wimbledon, three-time champion at Queen's Club. Titles Andy Murray hasn't won in the city of London: the ATP World Tour Finals.

Stage is set for ATP World Tour Finals in London

​In the four times Murray has competed at the London rendition of the Finals (he did not play last year due to back surgery) he has qualified out of his group just twice, losing in the semifinals in 2010 and 2012. He's in the tough Group B along with Federer, KeiNishikori and MilosRaonic, all of whom enter the tournament in good form. Murray's non-stop play after the U.S. Open -- he's played six tournaments in six weeks -- ended up being exactly what he needed. He won two titles, gained confidence and got the sort of "ugly wins" that you need to prove to yourself that you can win without playing your best.

Murray has now put himself in position to finish the year at No. 4. The one thing still missing from his 2014 resume is a big win. He's 4-9 against top ten opposition this year, with those four wins coming against Cilic, David Ferrer and Jo-Wilfried Tsonga. This season he's gone 0-4 against Djokovic and 0-2 against Federer. He'll play Federer in group play and could play Djokovic if he qualifies for the semifinals.

Will Marin Cilic be rested or rusty?

No one wants to write Cilic's U.S. Open title run as a fluke. Beating Federer the way he did wasn't accidental, and neither was winning his last three matches at that tournament without losing a set. That wasn't luck. That was talent.

Can he can summon that level on a consistent basis? Cilic sputtered through the post-U.S. Open Asian swing but rebounded to win the title in Moscow. Then he pulled out of the rest of the indoor season with a right arm injury. In London he'll get a crack at Djokovic, Wawrinka and Berdych, and if he's 100 percent, he has every chance to qualify for the semifinals.

Can Kei Nishikori and Milos Raonic put a youthful stamp on the tournament?

As the two youngest men in the tournament, Nishikori and Raonic will have to battle it out in the tougher Group B, which includes Murray and Federer. Raonic's redeemed his poor fall season with one of his best tournament performances of the year, beating Federer and Berdych to make the Bercy final.

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​That straight set win over Federer was the biggest win of his career and it may serve as a launching pad for him into that group of "second line" players who can beat the big guys on any given day.

Nishikori is already one of those guys. He spent the season shattering every milestone for an Asian player and he's 2-2 against both Djokovic and Federer. If he can play at his top level he's the easy dark horse pick for the title.

Can Tomas Berdych win the biggest title of his career?

He's tennis' version of The Invisible Man. Always around, always a theoretical threat, but rarely ever memorable. It's easy to forget that the 29-year-old is a Wimbledon finalist, has an ATP Masters 1000 title under his belt and multiple Davis Cup titles. He'll finish inside the top ten for the fifth consecutive year. He's always around in the late stages of tournaments, but overall he's won just 10 titles in his career. Getting his hands on the trophy in London would be a huge boost. Berdych has qualified for the semifinals just once in his four previous appearances, but the No. 2 qualifying spot out of Group A is wide open.

Will the Bryans win their first year-end title since 2009?

The Bryans have won every other Slam and ATP Masters 1000 more recently than their last Finals trophy. They've already clinched the year-end No. 1 ranking, but a win in London would round out their title count to ten for 2014. And who doesn't love round numbers?