Khachanov, ranked 808th in the world and 1-1 in main draw matches in 2013 before this week, ousted third-seeded Janko Tipsarevic 6-4, 6-4. Khachanov was invited to the tournament as a wild-card entrant and has made the most of the opportunity. He beat Albert Ramos in the first round and Tipsarevic in the second.
Khachanov had 14 aces and won nearly three-quarters of the points on serve Wednesday. He didn't face a break point.
Golubev, a qualifier, defeated sixth-seeded Horacio Zeballos 6-3, 6-4. He lost nine points in 10 games serving. Four of those came in one game as he saved the only break point Zeballos had.
The first round wrapped up with three matches, including fifth-seeded Denis Istomin taking out Andrey Kuznetsov 6-0, 2-6, 6-1. Teymuraz Gabashvili got by eighth-seeded Adrian Mannarino 3-6, 6-4, 6-4 and Ivo Karlovic beat Denis Kudla 6-2, 6-3 in other first-round matches.