Andy Murray gave Stan Wawrinka a taste of his own medicine by knocking the US Open champion out of the ATP World Tour Finals and sealing his place in the semis.
Wawrinka beat Murray in their final round-robin match at the O2 Arena last year to reach the last four and end the Brit's season, but this time it was the top seed who went through at the expense of the world number three.
World number one Murray, battling with Novak Djokovic to finish the year at the top of the rankings, and Kei Nishikori advance from Group John McEnroe after the home favourite won 6-4 6-2.
Milos Raonic stands in the way of Murray, who has now won 22 matches in a row, and a first appearance in the final of the glitzy event, with Djokovic and Nishikori contesting the other semi-final.
Murray, whose brother Jamie sealed top spot in the men's doubles rankings earlier on Friday, passed yet another stamina test to get past Nishikori in the longest ever ATP World Tour Finals match on Wednesday, but was in no mood to hang around two days later.
Wawrinka had advanced from the group stage in each of the last three years and started with a hold to love, but hammered his racquet down in reaction to going a break down at 4-3 when he sent a backhand into the net after Murray had a stroke of luck with a net cord.
Third seed Wawrinka saved three set points before holding with a sublime backhand winner to make it 5-4, but the brilliant Murray served out the set to seal his place in the semi-final.
He maintained his momentum at the start of the second, breaking in the first game when the disgruntled Swiss sent a miscued backhand into the crowd.
Wawrinka made a mess of his racquet after going two breaks down at 3-0, offering it is a souvenir to a spectator after he was given a violation, and it was only a matter of time before Murray wrapped up an emphatic victory in an hour and 26 minutes.
Murray  bt Wawrinka  6-4 6-2
Murray - 15/13
Murray - 3
Wawrinka - 7
BREAK POINTS WON
Murray - 3/7
Wawrinka - 0/2
FIRST SERVE PERCENTAGE
Murray - 59
Wawrinka - 61
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Murray - 87/57
Wawrinka - 66/42
Murray - 67
Wawrinka - 5