Five vie to fill ATP World Tour Finals place left vacant by Andy Murray

The British number one is still recovering from back surgery

Murray will not be playing at the O2 Arena next month (Getty Images)

Andy Murray's announcement that he is withdrawing from next month's Barclays ATP World Tour Finals in London may have been the least surprising news of the week, but word of the Scot's decision following his back surgery last month will have sent a buzz around the locker room at the Shanghai Rolex Masters.

Murray was one of four players – along with Rafael Nadal, Novak Djokovic and David Ferrer – who had qualified to play in the season's finale at the O2 Arena, but his withdrawal will open up an opportunity for someone else. The line-up comprises the eight players (fitness permitting) who have won the most ranking points in the year.

With Tomas Berdych and Juan Martin del Potro strongly placed at No 5 and No 6, five players appear to be in serious contention for the remaining three places. Roger Federer, Stanislas Wawrinka, Richard Gasquet, Milos Raonic and Jo-Wilfried Tsonga occupy the positions from No 7 to No 11. The biggest points are on offer here and at the Paris Masters later this month. Gasquet, who currently occupies the last London berth, will be kicking himself for losing to Vasek Pospisil first time out here, especially as his four main rivals all won their opening matches.

When you are Federer and have played in the season-ending finale for the last 11 years in succession, earning a place in the field might appear like no big deal. When you are 28-year-old Wawrinka and contemplating the prospect of taking part in the showcase event for the first time, it is a thought to set the pulse racing. "It would be just amazing, a dream for me to play in London," Wawrinka said after his hard-fought 6-4, 3-6, 7-6 victory over Kevin Anderson.

Federer was a break down against Andreas Seppi before winning 6-4, 6-3, while Djokovic crushed Marcel Granollers 6-2, 6-0 and Nadal beat Alexandr Dolgopolov 6-3, 6-2 to reach the last 16. Del Potro and Berdych both had to overcome physical problems before making the third round. Berdych recovered from a back problem to beat Feliciano Lopez 7-6, 6-2, while Del Potro had to contend with a fever before beating Philipp Kohlschreiber 3-6, 6-3, 7-6.