It was indeed some escape for Murray, who also trailed the left-hander 3-1 in the third, took a medical time out for a toe issue to end the fourth and was behind by a break at 3-2 in the fifth.
Ultimately, Murray played the big points better on Arthur Ashe Stadium in Flushing Meadows, New York, going 4-for-6 on break points compared to the 49th-ranked Nishioka’s 5-for-16 in their first meeting.
That included saving the match point at 5-6 in the fourth when Nishioka sent his return from a first serve long.
Murray became the second British player in as many days to fend off a match point and rally from two sets down after Cameron Norrie did the same against Diego Schwartzman.
The three-time grand slam champion last contested a singles grand slam match at the 2019 Australian Open in what many thought would be his final tournament.
Hampered severely by hip issues, the Scot said prior to Melbourne he was calling it quits but hoped to bid adieu at his home grand slam tournament, Wimbledon.
But after taking one of the game’s toughest competitors, Roberto Bautista Agut, to five sets — yes, five more sets — the father of three opted for the hip resurfacing operation in an attempt to keep things going.
Promising showing last week
“I felt way better today at the end of that match than I did when I played Bautista in Australia,” said Murray. “I’m not sitting here with my hip throbbing and aching. I’ll be able to sleep fine tonight and things like that.”
No fans are on site due to the coronavirus pandemic but the likes of Naomi Osaka, Dominic Thiem and Grigor Dimitrov took in the action from their luxury corporate suites on center court. All seeded players in singles were given the vacant suites.
Murray said he drew strength from seeing that brother Jamie — a doubles specialist — and father in-law Nigel Sears were also among those watching him.
“In some ways that can be a little bit distracting if you look up and you’ve got guys that are in the top five, top 10 in the world watching you and stuff,” said Murray.
“But for me, I had my father-in-law there. I had my brother there with his coach watching. There was a few of the British players that came out to watch and support, as well.
“Although the atmosphere was very flat overall, at the end of the match and as I was starting to turn it around, I could at least look up and see some faces in different points of the court to give me a little bit of encouragement, which definitely, definitely helped.”
Murray shook his fist after Nishioka’s overhead from a superb lob landed long on the final point. He hadn’t tasted victory at a grand slam in singles since the 2018 US Open.
“I think it was pretty emotional straight after the match finished,” he said. “When I got back to the locker room, sort of look at my phone, see the messages from family and friends, the team and stuff.
“They’re the people that have kind of seen me go through everything, been there, seen the tough times. I don’t know how many of us actually believed I’d be back kind of winning matches like that.
“Today’s win meant a lot. A lot’s gone into it.”
Murray has loved playing at the tournament ever since he won the juniors in 2004. His slam breakthrough came at Flushing Meadows in 2012 and he has now come back from two-set deficits four times at the US Open, more than at any other slam. Three have come against left-handers.
His next opponent is one of the game’s brightest young stars, Canada’s Felix Auger Aliassime.
Dedicates win to Suarez Navarro
Two-time grand slam winner Garbine Muguruza played her first match since February and downed another Japanese player, Nao Hibino, 6-4 6-4 earlier Tuesday.
The former world No. 6 with the glorious one-handed backhand is one of the tour’s most liked players.
“When we spoke a few days ago, when she gave me the news, I was, I think, shocked, because I was expecting to see her in this tournament,” Muguruza said to reporters. “She’s such a nice woman, so sweet, so kind, so humble.
“When these things happen to these good people, I feel so sad about it. So I know she was watching my match, and we talked a little bit.
“I, for sure, will dedicate this win to her, because I want her to feel that we are behind her, that I am behind her, and I will go and see her at some point when it is fine.”
Serena Williams, who played mixed doubles with Murray at Wimbledon last year, opened her bid for a 24th major with a 7-5 6-3 win over Kristie Ahn.
Getting to 24 would see Williams tie Margaret Court for the all-time record but the 38-year-old took sole possession of top spot in US Open singles wins with 102 — one more than Chris Evert — by defeating Ahn.
The key moment might have come when Williams hit two straight aces and another big serve to hold from 4-4, 30-40 in the first.
Her buildup has been marked by upset losses last week and also in Lexington, Kentucky, but the American has never lost, like Murray, in the first round of the US Open.