Top seed Roger Federer is on course for a seventh title at his home tournament in Basel.
Federer was given a slight scare by David Goffin before he prevailed 6-3 3-6 6-1 to reach the Swiss Indoors semi-finals.
The first set against Goffin flew by with Federer at his clinical best, taking the one break point on offer while saving two on his serve.
The Belgian thoroughly deserved to level in the second and Federer had to shift gears to race through the final set, with the extra backing of his home crowd.
Federer’s semi-final opponent will be Jack Sock after the American overcame compatriot, Donald Young, 5-7 6-4 6-2.