John Isner was not going to be denied on Wednesday as the second-seeded American fended off a match point and defeated Tunisian Malek Jaziri, 6-3, 3-6, 7-6 (6) at the ASB Classic in Auckland, New Zealand.
Isner was able to keep his aspirations of a third title at this tournament afloat by returning a stiff backhand volley past Jaziri in the third-set tiebreaker.
The 6-foot-10 Isner won the next two points, highlighted by a strong backhand volley down the line to end the match.
Isner advances to the second round of the tournament to face seventh-seeded countryman Steve Johnson, who benefited from a stellar service game to bounce Yen Hsun Lu if Taiwan, 6-4, 7-6 (4).
Johnson converted 31 of his 33 serves.
Dutchman Robin Haase fired aces to upset four-time champion David Ferrer of Spain, 2-6, 6-4, 7-6 (4). The 29-year-old saved six of nine break points to dispatch the third-seeded Ferrer and complete his match in two hours.
Joao Sousa of Portugal needed nearly half that much time to dismiss British qualifier Brydan Klein, 6-3, 6-4.
Fourth-seeded Jack Sock outlasted fellow American Ryan Harrison, 7-6 (5), 4-6, 6-1 to set up a match with Frenchman Jeremy Chardy, who received a walkover when sixth-seeded Spaniard Feliciano Lopez withdrew before their match.
Also on Wednesday, eighth-seeded Cypriot Marcos Baghdatis will square off against 2015 champion Jiri Vesely of the Czech Republic in the second round.
Baghdatis recorded 12 aces to defeat German wild card Dustin Brown, 4-6, 7-6 (4), 6-4, while Vesely had 15 aces in his 6-7 (6), 7-5, 6-3 triumph over Jose Statham of New Zealand, who replaced top-seeded Roberto Bautista Agut.