"I never would have imagined doing as well as I have done on the pro tour and doing it for so long," said Isner. "I know what it takes to do well and win matches, compete hard and stay healthy, so I am just going to continue to do that.
"You need to put yourself in the right positions. In Paris last year the draw had opened up for everyone and I was the highest-ranked person left in the semifinals but I lost. My compatriot Jack [Sock] won that tournament and he shot up into the top 10."
Isner's fame has been built around his height - 2.08m - and his incredible serve. Last year at Newport he became just the second player since 1991 not to face a single break point on the way to winning a title.
Despite being one of the tour veterans, Isner, who got married last month to Madison McKinley, retains a laconic, laidback persona.
That was demonstrated earlier this week when he was guest umpire for a charity match, as part of a Moet and Chandon promotion.
Isner, who looked like he was sitting on a step-ladder in the chair, cracked jokes constantly and was at ease with the two star-struck Auckland club players.
"I don't think it's something I am going to pursue once my tennis career is over," laughed Isner. "It's not a good spot to be in, when you have players competing and getting angry with you ... so I think I will stay away from that."
Isner is part of a bumper schedule today, that includes defending champion Jack Sock, world No12 Juan Martin del Potro, four-time winner David Ferrer and Canadian teenager Denis Shapovalov.
Yesterday, Steve Johnson beat Italian outsider Liam Caruana 7-5, 7-6 (4), while world No33 Pablo Cuevas was relatively untroubled against Taro Daniel, winning 6-3 6-2 win in just over an hour. Lucas Lacko made the most of his call-up as a lucky loser to progress to get past Greek wildcard Stefanos Tsitsipas 6-3, 6-7 (5), 6-3 and will meet Robin Haase today, the Dutchman coming back to beat qualifier Casper Ruud in three sets.
The 2015 champion JiriVesely and German Peter Gojowczyk both came through three set battles with qualifiers.
Order of play
Centre Court from 12.30pm
[5] Roberto Bautista Agut v Steve Johnson
[1] Jack Sock v Peter Gojowczyk
[7] David Ferrer v Joao Sousa
From 7pm
[2] Juan Martin Del Potro v Denis Shapovalov
[4] John Isner v Hyeon Chung
Grandstand Court from 12.30pm
[3] Sam Querry v Jiri Vesely
[6] Pablo Cuevas v Karen Khachanov