Andy Murray
Murray gains momentum ahead of ATP Finals. (Getty Images/Zhong Zhi)

Andy Murray has reached the semi-finals of the Valencia Open after defeating Kevin Anderson to keep on track for qualification for the ATP World Tour Finals in London.

The British number one bested his South African opponent despite dropping the first set to secure a 6-7 (3-7) 6-4 6-4 win, his 16th in his last 18 matches.

Murray will face either Thomaz Bellucci or David Ferrer in Saturday's semi-final with 500 ATP points awarded to Sunday's winner.

Murray currently sits in eighth place in the rankings and could yet jump into fifth should he reign in Spain, with the top eight qualifying for the season-ending event at London's 02 Arena.

Ferrer is Murray's nearest rival in the race for a top eight spot, sitting in a spot behind him in ninth position.

Murray surrendered the opening set in Friday's contest, falling a break behind after losing two service games thanks to a series of double faults. Murray battled back to force a tie break but the inconsistency he showed throughout the set remerged as Anderson took the tie break.

Murray levelled things up in the second however before seeing out the win in the decisive third.