Rafael Nadal and Marin Cilic meet in the other semi-final – but that could be the only game played on Saturday in Shanghai.
The 36-year-old Federer was relatively untroubled as he eased to a 7-5, 6-4 victory over the unseeded Gasquet.
He is scheduled to face Del Potro in the last four, although the Argentine’s participation is in doubt after he injured a wrist in his quarter-final victory.
Del Potro injured his wrist today and may now have to withdraw from the tournament.It would mean Federer has an extra day to prepare for a potential final with his arch enemy Nadal.
The Argentine fell on his left hand at the start of the third set of this tightly-contested quarter-final.