With no breaks of serve, the first set went into a tiebreak. As Isner stormed to a 5-0 lead, there was no way back for the Belgian.
Isner secured himself a crucial break at the beginning of the second set and holding his serve till the end, he set up a second round encounter against Tunisian Malek Jaziri, who ousted Yen-Hsun Lu in three sets 7-6 (10) 4-6 6-3.
The big surprise of the day came in the match between Czech Tomas Berdych and Steve Darcis, the Belgian prevailing 6-4 6-4. 14th seed Fernando Verdasco also bowed out of the tournament after Denis Istomin dismissed him in straight sets 6-4 7-6 (9).
In the other first round matches, Grigor Dimitrov of Bulgaria beat Lukasz Kubot of Poland 6-3 7-6 (4) and Philipp Petzschner ousted Lukas Lacko of Slovakia 7-6 (5) 6-1.