Andy Murray suffered his joint-heaviest ever tour defeat to crash out of the ATP World Tour Finals courtesy of a virtuoso display from six-time champion Roger Federer at the O2 Arena in London.
Requiring a two-set win to secure his place in the last four, Murray was the victim of a typically stylish Federer display as the world No.2 won 6-0 6-1 to end the Briton's season in emphatic fashion.
The result confirms debutant Kei Nishikori's place in the knock-out phase and he will join Federer in Saturday's two semi-final matches as the qualifiers from Group B.
But following a season in which Murray claimed three minor tour titles on his way to scraping into the finale to the ATP season and dropped to his lowest world ranking for six years, defeat is a reminder of the work required to return to the summit of the sport following back surgery last year.
The loss was the second time Murray had been defeated while recording just a single game on the professional tour, his heaviest reverse since the 6-0 6-1 loss to Novak Djokovic in Miami in 2007.
Following Nishikori's three-set win over alternate David Ferrer, Murray had his destiny all in his own hands with the knowledge that a two-set victory over the already-qualifier Federer would be enough to reach a fourth semi-final at the ATP Finals.
Despite having already secured a place in the last four for the 12th time in 13 outings at the tournament Federer still harbored hopes of finishing the year as world No.1 as he closed in on an 1,000th career win.
Murray looked set for a dream start in pursuit of a first straight sets win over Federer for 25 months when he launched into a 0-30 lead in the Swiss' opening service game, but in a passage of play which worked to define much of his year the Brit contrived to allow his opponent to wriggle away.
It would be a chance Murray would live to regret spurning as Federer took the second of two break points as the Scot sent a forehand long, before the 17-time major win consolidated the advantage by holding serve to lead 3-0.
As Murray's frustration began to grow so did Federer's authority and he broke for a second time to love to leave the Scot's semi-final hopes hanging by a thread before taking the next two games without alarm to secure the opening set in just 24 minutes.
Having already contributed to Murray's exit, Federer piled the pain on his opponent and secured the first five games of the second set to mark a comfortable passage to the last four, claiming the straight sets win to keep the pressure on Djokovic for the year-end world No.1.