Wellington - Feliciano Lopez, playing his second match of the day, knocked top seed and world No 12 Fabio Fognini out of the ATP Auckland Classic on Wednesday to advance to the quarter-finals.
Third-seed Karen Khachanov was also eliminated, losing to Australian John Millman while the second and fourth seeds, Denis Shapovalov and John Isner, went through to the final eight.
The 38-year-old Lopez, the oldest player in the tournament and one of several players forced to double up following the rain disruption the previous day, played three sets in each match and spent four hours 25 minutes on court.
He began the day beating Pablo Andujar 3-6, 7-6 (7/4), 6-4 and after a three-hour rest, he came from behind to beat Fognini 3-6, 6-4, 6-3.
The 61st ranked Lopez believes the rain delay did him a favour.
"The first match was tough but I honestly think it was very helpful for me (before playing) against Fabio," Lopez said.
"It was my first match this year, it was two and a half hours on the court so that was very helpful for me and without that match, I don't think I could have played the way I did against Fabio."
Lopez will face Poland's Hubert Hurkacz in the quarter-finals after the sixth-seed put away Mikael Ymer of Sweden 6-2, 7-6 (7/2).
While Lopez found two matches beneficial, two other players required to play twice lost in the second round.
Italian Marco Cecchinato, who won a three-hour marathon against Leonardo Mayer in which the second set tie-break went to 20-18, was then beaten by Frenchman Ugo Humbert 6-1, 6-4
Andreas Seppi of Italy beat seventh seed Adrian Mannarino (FRA x7) in three sets before going down to Kyle Edmund 6-3, 7-6 (7/4).
Edmund will play two-time Auckland champion Isner in the quarter-finals after Isner, who had a first-round bye, opened his campaign with a three-set win over defending titleholder Tennys Sandgren.
Tournament fourth-seed Isner won 7-6 (7/3), 6-7 (1/7), 6-3, pulling away in the deciding set with the first service break of the match when Sandgren faltered at 2-2.
Until then, the pair had only been separated by tie breaks with Isner taking their previous encounter in Stockholm two years ago in three tie-break sets.
"I feel good about that," Isner said of finding a way around Sandgren's serve and dishing up 16 aces of his own.
After losing all three of his matches last week at the ATP Cup in Australia, Isner was relieved to register a win.
"The freshest memory I have right now is winning and playing a good third set, so I have to use that to gain momentum going forward," he said.
"I won a tie-breaker, he won a tie-breaker, there wasn't much separating us at all.
"Eventually I played a good game at 2-2 in the third and was able to break and give myself some momentum. It's a good sign."
In an all-Canada affair, Shapovalov beat Vasek Pospisil 6-4, 7-6 (7/2) while Millman dropped the first set against Khachanov before recovering to win 4-6, 6-3, 6-3.
Results from day three of the ATP Auckland Classic tennis tournament on Wednesday:
Marco Cecchinato (ITA) bt Leonardo Mayer (ARG) 7-6 (8/6), 6-7 (18/20), 7-6 (7/2)
Andreas Seppi (ITA) bt Adrian Mannarino (FRA x7) 3-6, 6-4, 6-4
Feliciano Lopez (ESP) bt Pablo Andujar (ESP) 3-6, 7-6 (7/4), 6-4
John Isner (USA x4) bt Tennys Sandgren (USA) 7-6 (7/3), 6-7 (7/1), 6-3
Feliciano Lopez (ESP) bt Fabio Fognini (ITA x1) 3-6, 6-4, 6-3
Benoit Paire (FRA x 5) bt Thiago Monteiro (BRA) 4-6, 6-4, 6-3
Hubert Hurkacz (POL x6) bt Mikael Ymer (SWE) 6-2, 7-6 (7/2)
Denis Shapovalov (CAN x2) bt Vasek Pospisil (CAN) 6-4, 7-6 (7/2)
Kyle Edmund (GBR) bt Andreas Seppi (ITA) 6-3, 7-6 (7/4)
Ugo Humbert (FRA) bt Marco Cecchinato (ITA) 6-1, 6-4
John Millman (AUS) bt Karen Khachanov (RUS x3) 4-6, 6-3, 6-3