Andy Murray faces Stan Wawrinka, Rafael Nadal and David Ferrer in his group for ATP Tour Finals

Andy Murray's ATP World Tour Finals group has been decided - here are the three men that he must overcome at The O2.

The world No 2 automatically started at the top of the Ilie Nastase group and avoided an immediate match with Roger Federer.

However, he must still pit his skills against three of the sport's finest players in the tournament, starting this Sunday, live on Sky Sports.

Stan Wawrinka (world No 4)

Murray's last match against Wawrinka was more than two years ago when the Swiss star claimed a straight sets wins in the US Open quarter-finals.

But Murray already holds two wins over on home soil as he defeated Wawrinka at Wimbledon in 2009 and also at the London 2012 Olympics on the way to winning gold in the men's singles.

Wawrinka, the reigning French Open champion, should supply the sternest test and their match will give a clear indication of whether the British No 1 can compete for the title in London.

Rafael Nadal (world No 5)

The pair most recently met at the Madrid Masters final in May, with Murray taking the title after an impressive 6-2 6-3 win on Nadal's preferred surface of clay.

But the 14-time Grand Slam champion has derailed Murray at major tournaments, claiming back-to-back semi-final wins at the US Open and Wimbledon in 2011.

Arguably the Scot has much improved since then, now sitting at No 2 in the world, and will start as favourite against Nadal, who has struggled for form during one of the most difficult years of his career.

David Ferrer (world No 7)

Ferrer, another Spanish player, took the last remaining spot in the group and has been a familiar foe this year.

Murray defeated the 33-year-old earlier this month at the Paris Masters and also holds another win over Ferrer in the French Open quarter-finals this June.

That performance against the clay-court specialist in Paris was particularly impressive and Murray, with four straight victories, should approach their latest encounter with plenty of confidence.

Watch day one of the ATP World Tour Finals from 12 noon this Sunday on Sky Sports 3.