David Goffin ended Roger Federer's bid for a seventh ATP Finals title by stunning the favorite 2-6, 6-3, 6-4 in the semifinals on Saturday.
The Belgian claimed the biggest win of his career and qualified for the final on Sunday, when he will face Grigor Dimitrov or Jack Sock. They play later Saturday.
Federer looked to be heading toward his 11th final at the elite season-ending tournament when he cruised through the first set, but Goffin took advantage of a drop in his play to level.
Despite having lost all six of his previous encounters with Federer, Goffin was able to execute better in the deciding set, breaking in the third game and producing a nerveless display of serving to seal victory.
Murray splits with coach
Former world number one Andy Murray announced he has split with coach Ivan Lendl for the second time as he works towards regaining full fitness for the 2018 season.
The 30-year-old Scot has enjoyed all of his Grand Slam success under the guidance of Lendl, securing a second Wimbledon title last year and another Olympic title in the second instalment of their fruitful partnership.
Overall, in his two spells with Lendl, Murray won three Grand Slams, two Olympic golds and reached the top of the rankings in a fearsomely competitive era of men's tennis featuring Roger Federer, Rafael Nadal and Novak Djokovic.
"I'm thankful to Ivan for all his help and guidance over the years. We've had great success and learned a lot as a team," Murray said on his website.