The Aberdeen rider took victory at London 2012 and then watched wife Lora win her first gold at Rio 2016, where he narrowly missed out and settled for silver.
Both produced their perfect race in Tokyo, Neil obliterating his own tandem kilo world record with Matt Rotherham and Lora doing the same in the 3000m individual pursuit with Corinne Hall.
They now take pride of place alongside Laura and Jason Kenny as another of British cycling’s golden couples.
"The Kennys are an incredible family so to be even in the same sentence as them is amazing,” he said.
“Lora and I have had mixed success over the years, We thought the moment might not actually come when we both won gold.
“She obliterated the world record, and I have as well. Nobody even dreams of this, it's way beyond anything you can imagine.
“I knew how hard Lora works, she's been fighting for this, and she deserves every bit of it.”
The likeable couple set up a life coaching business together in 2017 and Neil credits Lora with helping him accept his impairment, which he struggled with in his younger years.
Fachie fully exorcised the demands of five years ago and crashed through his own lifetime best of 59.278 with a remarkable ride to 58.038 in Tokyo.
“You’re always aspiring for the perfect race, and it’s something you never achieve but I feel like that was pretty damn close,” said the 37-year-old.
“It was a case of just keeping smooth and keeping strong. We knew it would take a new world record to win, when Matt turned around to me and told me the time, it was mind-blowing.
“We came in as favourites in Rio and were outdone by a better bike. It was a hard defeat to take and then a few months later I lost both of my world titles, so at that point I thought the end of my career was coming.
“Then Matt and I teamed up and the rest is history, as they say.
“It was an impressive record before and it's going to be hard to beat now. It's an incredible journey and an incredible moment.”
There was a podium place for Killearn sighted pilot Lewis Stewart, who won silver with James Ball behind Fachie and Rotherham.
And Blairdrummond’s Jenny Holl, 21, managed bronze with Sophie Unwin in the 3000m.
It was an incredible morning for British cycling at the Izu Velodrome, yielding five medals to swell the track medal haul to six golds and 14 gongs overall.
It was rounded off by a stunning ride to C1-5 mixed team sprint gold from the British trio of Kadeena Cox, Jaco van Gass and Jody Cundy.
The trio combined to break the world record and overhaul China, previous world record holders, favourites and 0.5 seconds quicker than the ParalympicsGB trio in qualifying.
Cox said: “Beating the boys makes it even sweeter for me. I could have been scared as the only woman racing a team of amazing guys, but I’m a great athlete in my own right.
“I’m just trying to show people that if you put your mind to something, you can absolutely nail it. I’ve not done sub-20 before and I’ve done it twice in 48 hours now!”
Elsewhere, Musselburgh-born Afghan vet Micky Yule got his tactics spot on as he captured powerlifting bronze.
Yule, who lost both his legs after stepping on an explosive device in Helmand province 11 years ago, lifted 182kg - three times his body weight - to reach the rostrum.
"We played a dangerous game of poker and we won and you know what – we never even had anything in our hand," he joked.
"It just means everything and it seems like a bit of a dream at the moment because I wasn’t the strongest.”
Meanwhile, Stirling triathlete Alison Peasgood narrowly missed out on a second Paralympic medal but said just making it to the start line was victory in itself.
On the eve of the Games, she was on crutches with a back injury and was unsure she’d even be able to race, finishing fourth in the PTVI2 event.
“Obviously it's been a long journey. I was very ill in 2019 and to get back and into some form in 2020 I was excited to race, but then it got cancelled,” she said.
“I was on crutches at the holding camp and I didn't think this was possible. Even up until last week we still thought we might be flying back.
“So to be here and actually be competitive, it’s pretty special.”
Scottish Commonwealth Games star Stef Reid produced the second-best leap of her career but it was only good enough for fourth in the long jump.
Reid, a silver medallist in the T62 event at London and Rio, produced a huge leap of 5.75m but still finished just four centimetres off the podium.
"Fourth is new to me but that was my best Paralympic performance ever, so it's bittersweet," she said, with the event won by Holland's Fleur Jong in a 6.16m world record.
There was more golden glory for 19-year-old Maisie Summers-Newton in the pool as she romped to 100m breaststroke gold.
With idol Ellie Simmonds again in her wake, finishing fourth, the debutant broke the Games record and touched the wall in 1:32.34 to claim victory.
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