The match was just the second in their 10 meetings in which at least one set didn't go a tiebreaker.
''That one's not the norm for us,'' said Isner, the runner-up to Rafael Nadal in last year's tournament. ''I thought I played well from the very beginning. I was seeing the ball well. From the first warmup ball, I felt like it was going to be a good night. It helped that Kevin didn't play as well as he normally plays. A lot of things went well.''
Fifteenth-seeded Fabio Fognini avoided an upset, pulling out a 6-4, 4-6, 7-6 (5) win over Edouard Roger-Vasselin. Also, Gilles Simon earned a second-round match against top-seeded Novak Djokovic with a 6-3, 6-2 win over qualifier Bernard Tomic.
In the men's draw, 16th-seeded Tommy Robredo survived a first-set tiebreaker to advance to the second round with a 7-6 (5), 6-3 win over wild-card American Jack Sock.
Fernando Verdasco needed three sets to eliminate Marcel Granollers, 5-7, 6-3, 7-6 (5). Three other players advanced with first career wins over their opponents, led by qualifier Benjamin Becker, whose 7-6 (5), 6-4 upset of Ivo Karlovic was the German's first win in seven matches against the 28th-ranked Croatian. Also, Philipp Kohlschreiber beat Jeremy Chardy, 6-3, 4-6, 6-4, the 24th-ranked German's first win in three matches against the Frenchman, and Lu Yen-Hsun advanced with a 6-3, 6-4 win Denis Istomin, Lu's first win in four matches against Istomin.
Qualifier Marinko Matosevic moved on with a 6-4, 7-6 (4) win over Nicolas Mahut, while Gael Monfils needed three sets to get past 63rd-ranked Federico Delbonis, 6-3, 3-6, 6-3. No. 37 Joao Sousa was tested by qualifier Chase Buchanan before prevailing, 5-7, 7-6 (3), 7-6 (5), but Jerzy Janowicz easily advanced with a 6-4, 6-4 win over Teymuraz Gabashvili.