Australia's Alex de Minaur has been made to fight hard but has reached the last 16 at the Shanghai Masters.
De Minaur came up against Japanese qualifier Rei Sakamoto - a 20-year-old ranked 137th compared to the Australia's No.9 seed and world ranking.
The 27-year-old de Minaur had to dig deep but ultimately prevailed 7-6 (8-6) 6-4 in an hour and 34 minutes to progress to a meeting with 26th-seeded Russian Karen Khachanov.