Two-time winner John Isner has knocked out defending champion Tennys Sandgren in three sets at the Auckland Open.
The only previous meeting between the American pair, in Stockholm in 2018, went to three tie-breaks.
Isner finally bucked that trend on Wednesday when he claimed the first break in the fifth game of the final set on his way to a 7-6 (7-3) 6-7 (1-7) 6-3 triumph.
"It's always a tough match playing Tennys," Isner said of the second-round match.
"He does a lot of things really, really well on the court and when he and I match up it's inevitably going to be close and that was the case today.
"I'm very happy to get through in somewhat comfortable fashion."
The fourth-seeded Isner won the tournament in 2010 - his first ATP title - and again in 2014 for his only tournament wins outside the United States.
While he has returned regularly, the last few years have not been as kind.
"I've always been a pretty slow starter, so I'm very happy to win this match today," Isner said.
"I've lost my first match here the last three years, I think. So I've bucked that trend in 2020 and I'm very happy about I hope I can play better tomorrow."
Organisers were forced to schedule 18 matches on Wednesday to make up for time lost the day before when only two matches were completed due to rain.
Feliciano Lopez was among players who had to play two matches on the same day, and in his second, he upset top seed Fabio Fognini of Italy 3-6 6-4 6-4.
Lopez was on court for two-and-a-half hours for a 3-6 7-6 (7-4) 6-4 first-round win over compatriot Pablo Andujar.
"Not bad for a 38-year-old," Lopez said.