Raonic, runner-up at Wimbledon earlier this year, took the opener on a tie break before he closed out a 7-6, 6-3 victory as he followed Novak Djokovic into the semi-finals.

The Canadian has been in superb form throughout 2016 and will be bidding to end it on the best possible high by lifting the trophy on Sunday (November 20).

His opponent in the last four will be decided tomorrow, with Britain's Andy Murray taking on Switzerland's Stanislas Wawrinka and Japan's Kei Nishikori facing Marin Cilic of Croatia.

Murray, the current world number one, Wawrinka and Nishikori are vying for the two available spots from their group.

"I got fortunate at the end of the first set to hit three aces," Raonic said.

"I stuck with my weapons and I was fortunate to get through."

In the other match in the Ivan Lendl Group, Djokovic ensured he progressed to the semi-finals with his 100 per cent record in tact as he beat Belgium's David Goffin, who stood in for Gael Monfils after the Frenchman withdrew from injury, 6-1, 6-2.

Djokovic, whose temper has frayed on a couple of occasions during the competition, had already qualified for the last four and picked up his third straight win with a commanding display in a match which lasted just 69 minutes.

The result ensures he keeps the pressure on Murray, the Olympic champion who recently replaced the Serbian as world number one.

Djokovic, winner of 12 Grand Slams, needs to better the Briton's performance at the event if he is to regain his place at the summit of the world rankings.

Goffin was a reserve for the tournament and was handed an ATP World Tour Finals debut when Monfils pulled out due to a recurring rib injury.