After months of relentless training, endless miles clocked up, and the sacrifice of time away from family, Mo Farah was almost undone after he suffered a dreaded 'stitch' halfway through the 5000m final.
His scent for a battle ripe, Farah completed the double-double on Friday, the holy grail of distance running - the 5000 and 10 000 Olympic and world titles held simultaneously.
It turns out that the Briton – now elevated without doubt into the pantheon of distance greats alongside Emil Zatopek, Haile Gebrselassie and Kenenisa Bekele – had most to worry about from an intense pain under his ribcage, and not the battery of Ethiopians and Kenyans lining up to dethrone him.
The men from Africa tried and failed at last year's Olympics. In Moscow, they again played right into his hands, the slow pace in both races allowing Farah to be where he wanted to be - ahead at the bell and in position to kick from the front.
"In my honest opinion I thought the race would have gone harder - because the guys are thinking 'he's already done 25 laps around the track, plus the 5k heat,'" said the 30-year-old after digging deep to retain his 5,000 metres title, holding off Ethiopian Hagos Gebrhiwet and Kenyan Isiah Kiplangat Koech.
"It suited me today. I had a stitch from about eight laps to go and I was kind of pushing my stomach in, but then the pace slowed down and I tried to forget about it and come through."
Becoming the second man after Bekele to hold the Olympic and world championship distance double at the same time, Farah reflected on his journey to becoming a champion.
The road, he said, had not always been paved with gold.
"I've learned a lot in my career. Many people forget I didn't became a great athlete overnight. It's been years of struggle.
"From winning medals as a junior, from finishing sixth or seventh in a world championship, since 2010 becoming double European champion and then making that big breakthrough... to be coached by Alberto Salazar, and in terms of myself just improving one or two per cent - that's the difference between becoming a champion and finishing sixth.
"I never thought in my career that I'd be able to achieve something like this."
Despite all the adulation surround his London success, Farah said he considered Friday's win to be the "sweetest of all".
"My legs were heavier than the rest of the guys who didn't run in the 10k," he said. "Credit to Koech, he pushed on. The guys are still trying."
Farah is the master of winning tactical races off a slow pace and said medals, and not world records, were the more important.
"I would like to run a decent time, it would be great," hes aid. "But for me, the most important thing is trying to win medals in my career. The great athlete Kenenisa Bekele has both of the (world 5,000 and 10,000) records, it would be nice to get close to that."