Gregoire Barrere withstood a barrage of aces from John Isner and a change of court triggered by Cyclone Hale as he upset the American sixth seed at the Auckland Open.
French qualifier Barrere and US veteran Isner were forced indoors by the adverse weather threat in New Zealand, with the entire Tuesday schedule taking place on inside courts and without spectators.
Despite Isner rifling down 28 aces to move 10 away from becoming the first man to post 14,000 in ATP tour and grand slam events, Barrere stuck with him and pulled off a 6-7 (3-7) 7-6 (7-5) 6-3 victory.
He snatched the only break of the match in game eight of the deciding set, before serving out for victory, with the world number 88 firing down 10 aces himself across the contest.
Argentine seventh seed Sebastian Baez also fell at the last-32 stage, bowing out 7-6 (7-1) 6-1 to American wildcard Ben Shelton.
Serbian Laslo Djere set up a second-round clash with top seed Casper Ruud by edging out Spain's Jaume Munar 3-6 6-1 7-6 (7-4), while Czech Jiri Lehecka will face second seed Cameron Norrie next after sinking Brazilian fellow qualifier Thiago Monteiro 6-3 7-5.
Ruud and Norrie received first-round byes.
At Adelaide International 2, American eighth seed Tommy Paul battled past Australian Christopher O'Connell 6-4 7-5, setting up an appetising second-round clash with Britain's Jack Draper, who won through on Monday.
There was a home success for the Australian crowd to cheer, though, as qualifier John Millman, who beat Roger Federer at the 2018 US Open, this time dug deep for a 4-6 6-3 7-6 (8-6) win against Spain's Albert Ramos-Vinolas.