Neither player had an easy start, with points fought fiercely and Fils racing to a 40-0 lead in Van de Zandschulp's second service game. The Dutchman rallied to erase an early deficit before doing the same to pull alongside Fils at four games apiece.
Van de Zandschulp landed a late hit, breaking Fils to go up 6-5 and serve for the match, which was easier said than done, with Fils forcing two break points, but ultimately conceding the set to the energetic Dutchman.
The late break sent Fils haywire, with the Frenchman smashing his racket and throwing a water bottle in despair.
Van de Zandschulp continued his positive form in the second set, pulling away from the Frenchman with an early break but losing the advantage at the first opportunity, as Fils re-broke on love. The combative Dutchman pulled ahead again, however, overpowering Fils in a quick game to clinch a late advantage and soon play for the match.
Fils held a difficult service game to stay alive at 5-4 and kept up a strong fight as Van de Zandschulp served for the match. With match point on the line, Van de Zandschulp crucially missed a net smash to hand the initiative to Fils, but landed a phenomenal winner for deuce and got to match point after an unforced error from Fils.
The Frenchman recovered once more but missed a return and hit the net, giving Botic van de Zandschulp another upset win and sending the eighth seed packing in Shanghai.
With his third top-20 win of the season and his third fourth-round appearance at a Masters 1000 tournament, Van de Zandschulp set up a meeting with Spanish phenom Rafael Jodar.
