David Goffin stunned Roger Federer with a spirited fightback to knock out the six-time champion and reach the final at the season-ending ATP Finals.
The Belgian seventh seed came back from a set down to win 2-6 6-3 6-4 – his first victory in seven attempts against the 19-time Grand Slam champion.
Federer, 36, ends the year with 52 wins and five losses.
Bulgaria’s Grigor Dimitrov will face American Jack Sock in Saturday’s second singles semi-final at 20:00 GMT.
