Harrison breaks midway through the first set to take one set lead
The first five games went to the server in routine fashion with the returner not getting to deuce. It was in the sixth game that Harrison made his move.
After saving a break point at 30-40 with a crisp volley, the Frenchman found himself in trouble again, missing a forehand volley to give Harrison a second break point which the American converted with a forehand volley winner of his own.
Mahut broke back in large part to three Harrison errors off the ground, but again the Frenchman donated his serve with a couple of forehand errors. Given a second chance, Harrison closed out the set to love with an ace.
Harrison lets lead slip, regains edge late to take a two set lead
Mahut's ground game was not sharp and it let him down again as he was broken to begin the second set when, at 30-30, a pair of unforced errors handed Harrison the lead. As in the first set, Mahut pulled even as the American double-faulted at 15-40 for a 3-3 score.
Coming from 30-0 down, Harrison set up a break point, but Mahut duly duly saved it with a forehand winner. After saving a second break point, a third opportunity was presented to the American and he took it with a crisp backhand winner.
Harrison's serve was clicking and he closed the final two games of the set out with aces to take a two set lead.
Harrison runs away with the third set to cruise into the second round
Harrison continued to play solid tennis and after a love hold, he had 15-40 on Mahut's serve, but a couple of errors quickly nullified those chances and Mahut would hold for a 2-1 lead.
The next time the Frenchman served, he was in trouble again and at 30-30, gifted the break to the American with a pair of sloppy errors, one off of each wing. That would be all Harrison needed and he got an insurance break for a 5-2 lead.
Serving for the match, Harrison held to 15 when Mahut struck one final wayward backhand, the American moving on to face tenth seed Tomas Berdych in the second round.