Milos Raonic, Marin Cilic eye London

As the year draws to a close, several players are battling to reach the season-ending ATP World Tour Finals that start on November 9 in the English capital.

Only Novak Djokovic, Rafael Nadal and Roger Federer have booked their spots in the eight-man field so far.

Raonic and Cilic are among those competing for the other places and will be aiming to improve after poor Shanghai Masters campaigns.

Canadian Raonic retired in the second round in China with what was believed to be a fever, while US Open Cilic made an opening-round exit.

Raonic had reached the final in Tokyo, where he lost to local Kei Nishikori, before heading to China.

The ATP 250 event played on hard courts in Russia is an opportunity for both to return to some form.

But they will have plenty of competition from a strong field.

Latvian Ernests Gulbis is also looking to bounce back after a first-round loss to Mikhail Youzhny in Shanghai.

Home favourite Youzhny will compete after a good run at the Masters, where he reached the quarter-finals.

Fiery Italian Fabio Fognini and countryman Andreas Seppi - the 2012 champion - are in the field as well.

Spaniards Tommy Robredo and Roberto Bautista Agut are also capable of challenging if they can get through the early rounds.

Russian Evgeny Donskoy has received a wildcard and is due for improvement after what has been a disappointing 2014.