Khachanov broke for 2-1 and again for 5-2, clinching 6-2, with Sakamoto's sole resistance a deuce hold for 2-3 saving one break point.
Khachanov broke for 3-2 after Sakamoto saved two break points, then held for 6-4, though Sakamoto mounted a defiant deuce hold for 4-5 saving all four break points.