Konta hit the first serve of the contest at 12.30am, making it the latest start to a match at Melbourne Park and almost certainly in grand slam history. By the time Muguruza struck the winning shot to claim a 6-4 6-7 (3) 7-5 victory, it was 3.12am.
“I can’t believe there are still people watching at 3.15,” said Muguruza. “Who cares?”
“I’ll go for breakfast now,” she added.
This was still nowhere near the latest finish ever, which came in 2008 when Lleyton Hewitt and Marcos Baghdatis played a five-set match that finished at 4.33am.
“It wasn’t ideal for anyone,” said Konta. “I don’t think it’s ideal for anyone to do any physical activity when it’s bedtime, but it is what it is and both of us were in the same boat.
“I think it’s more important to focus on the level of the match we had because it was actually a very good match. It was unfortunate that more people couldn’t enjoy it during the day.”
Although Konta did not come out on top of this one, this was a performance from the British number one that harked back to her form of two years ago, when she appeared a legitimate grand slam challenger, and should give her plenty of confidence for the season ahead.
The match was going to be moved to Court Three, but that plan was shelved, remarkably, because of a lack of staff to clear seagull droppings off the court.
Around 1,000 spectators remained in Margaret Court Arena, although that number was soon reduced as two well-refreshed women were escorted out.
The last match between Konta and Muguruza at the US Open four years ago lasted more than three hours, so a late night clearly had the potential to turn into an early morning.
The British player made a poor start by dropping serve in the opening game but grew into the match thereafter and the pair were soon trading mighty groundstrokes.
Konta may be ranked well down on her career-high mark of four, achieved after her run to the Wimbledon semi-finals two years ago, but there have been signs the conviction in her game is returning.
At her best, the 27-year-old is a formidable ball-striker and she threatened to get back into the first set but was repelled by Muguruza, who has had her own struggles with form and fitness since winning her second slam title at SW19 in 2017.
Konta looked the better player in the early stages of the second set but could not get the break. It was a remarkable standard considering the hour and, after the British number one saved two break points at 4-4, the set headed into a tie-break.
Somehow Konta managed to find an even higher standard, striking the ball with ferocity and accuracy and then winning a HawkEye challenge to set up a decider.
As the crowd numbers dwindled still further, the pace on court certainly did not slacken, with neither woman giving an inch on serve.
It was not until the 12th game that Muguruza forced the first break point of the set, a match point, and took it to set up a third-round clash with Timea Bacsinszky.
“I think I played a great match and a lot to do with that is the chemistry between the two players and the way two game styles match up,” added Konta, who said she would look to build on her performance over the rest of the season.
“I’d like to think so. I look to take every opportunity to learn from every single match. I would have liked to have won and learned but it didn’t go my way.”