After the conclusion of the ATP 500 tournaments in Valencia and Basel, the Paris Masters remains for some of the top players in the world to secure their place at the ATP World Tour Finals in London.

British number one Andy Murray displayed remarkable resilience to save five match points on the way to beating Tommy Robredo in a three-set marathon in Spain,and that ensured that he capitalised on David Ferrer, Milos Raonic and Grigor Dimitrov failing reaching the final at either event.

However, with Rafael Nadal having revealed that he won't compete next month, six players are fighting for four places as they try to join Novak Djokovic, Roger Federer, Stanislas Wawrinka and Marin Cilic at the O2 Arena.

Below, Sports Mole assesses the six contenders and their chances in Paris this week.

Andy Murray

Points: 4,295

Race to London ranking: 5

Form: Murray has spent five exhausting weeks trying to remain in contention for London and that effort has been rewarded with back-to-back tournament wins in Vienna and Valencia. That has ensured that only an unlikely set of results will deny the Scot a top-nine spot, but he could require that cushion with little left in the tank for Paris.

Opening match in Paris: Lu Yen-Hsun or Julien Benneteau.

Potential route in draw: If he comes through his opening match, Murray will probably have to play Dimitrov, with all the pressure on the Bulgarian who needs to reach the final. The winner of that encounter is expected to have Djokovic in the quarter-finals.

Kei Nishikori

Points: 4,265

Race to London ranking: 6

Form: After his run to the US Open final, Kei Nishikori recorded successive tournament wins in Kuala Lumpar and Tokyo, but a surprise second-round exit in Shanghai to Jack Sock has seen the Japanese star take two weeks off to prepare for Paris, and probably London too. A last-eight appearance this week would guarantee his place.

Opening match in Paris: Tommy Robredo or Vasek Pospisil.

Potential route in draw: Nishikori is seeded to meet hometown favourite Jo-Wilfried Tsonga in the last 16 in Paris, with a last-eight showdown with Ferrer a possibility.

Tomas Berdych

Points: 4,105

Race to London ranking: 8

Form: Tomas Berdych followed up a final appearance in Beijing by reaching the last eight in Shanghai, but tiredness was probably a factor in his defeat to Gilles Simon. He responded by winning in Stockholm and despite being knocked out in the first round in Valencia last week, that has probably helped the big-hitting Czech ahead of Paris as he looks to earn his fifth appearance at the Tour Finals.

Opening match in Paris: Pierre-Hugues Herbert or Adrian Mannarino.

Potential route in draw: If, as expected, Berdych comes through his first match, he is likely to face Feliciano Lopez or Jerzy Janowicz, with Stanislas Wawrinka lying in wait in the last eight.

David Ferrer

Points: 3,865

Race to London ranking: 9

Form: Ferrer has played solidly enough in Shanghai, Vienna and Valencia, but defeats to Djokovic and twice to Murray has left him with work to do this week. The Spaniard will need to out-perform both Raonic and Dimitrov to reach the finals.

Opening match in Paris: Lukas Rosol or David Goffin.

Potential route in draw: Ferrer, who has an impressive record in Paris, is seeded to play Gilles Simon in the last 16 with either Tsonga or Nishikori expected to be the opposition in the quarter-finals.

Milos Raonic

Points: 3,840

Race to London ranking: 10

Form: Raonic had seemingly done enough to put himself in prime position for a place at the O2 Arena, but a disappointing few weeks means he was work to do in the French capital. The Canadian did reach the last eight in Basel last week before running into David Goffin but he realistically needs to reach a minimum of the semi-finals to have a chance of sneaking into the top nine.

Opening match in Paris: Jack Sock or Pablo Andujar.

Potential route in draw: Raonic is seeded to play Roberto Bautista Agut in the third round but his participation could be in doubt after withdrawing in Valencia. If Raonic makes the quarters, Federer could be his opposition in a showdown that he would probably have to win to seal his place in London.

Grigor Dimitrov

Points: 3,555

Race to London ranking: 11

Form: A poor effort on the Asia swing left Dimitrov adrift of his rivals but a runner-up place in Stockholm and a quarter-final defeat in Basel has at least kept him in with a chance to secure one of the remaining spots.

Opening match in Paris: Leonardo Mayer or Pablo Cuevas.

Potential route in draw: Dimitrov could face Murray in the third round should both players come through their second-round matches with Djokovic the possible opponent in the last eight. The Bulgarian realistically needs to reach the final to have any chance of reaching his first ATP World Tour Finals.