Stay up to date with the latest news
Subscribe to our telegram channel
The sixth-seeded Istomin, of Uzbekistan, wrapped 12 aces before overcoming speedy German Bjorn Phau 5-7, 7-5, 6-1.
In the second round, Denis Istomin will face Czech Lukas Rosol, who smacked 11 aces in topping Spaniard Daniel Gimeno-Traver 7-6 (11-9), 7-6 (7-2).