Isner won 7-6, 6-2, 7-6 against Frenchman Mahut in a contest every bit as low-key as their 11-hour epic last year was dramatic.
The first game of the match lasted less than a minute and although there were two tiebreaks the clash never threatened to live up to last year's three-day marathon, by far the longest match in tennis history.
Isner took control by winning the first-set tiebreak and Frenchman Mahut never looked like fighting back in a subdued atmosphere on a windy Court Three.
"The phenomenon that was created around last year's match has been difficult for the two of us to tackle," 94th-ranked Mahut said.
"He played better than me today. The atmosphere was not as huge as I was waiting for," added the Frenchman, who despite his dejected demeanour still found room for humour.
"I'm sure you're all disappointed about today," he joked. The pair embraced warmly at the net and exchanged kind words after the match.
"'Hey, buddy. I want to see you in the second week of this event,' he told me," Isner said.
