Raonic endured an injury-filled year in 2019.
No. 6 Ugo Humbert of France advanced by beating 2018 champion Frances Tiafoe 6-1, 6-2. Humbert will next play unseeded Yoshihito Nishioka of Japan, who rallied past 18-year-old American Brandon Nakashima 3-6, 7-6 (5), 6-4.
Humbert and Nishioka both are seeking their second career ATP Tour title.