The Canadian had been battling with the Haas of Schumacher for 15th place at that time, with a vigorous scrap leading to pick-up on Latifi's tyres and a subsequent mistake.
The incident would turn the championship race on its head, Lewis Hamilton having led by 12 seconds with five laps remaining; only to see that advantage erased with Max Verstappen behind now on fresh soft compound tyres which he'd use to make a decisive last-lap move.
For his part, Latifi was disappointed.
“It was a tough race out there today and we were struggling for pace throughout,” he said.
“Towards the end of the grand prix, I was racing with Mick Schumacher and was forced slightly wide, but fairly, at Turn 9.
“My tyres got dirty from running off track and I subsequently made a small mistake and unfortunately crashed.
“This obviously wasn't how I wanted to end our season, so it's disappointing.”
Russell also was a non-finisher at Yas Marina, due to a gearbox issue. Even still, Williams clung on to eighth in the constructors' championship as rivals Alfa Romeo similarly suffered a double DNF.
“It wasn't the way that we wanted to secure our championship position; however, we can still be proud of the work we did earlier in the year which got us into a strong position,” said Williams head of vehicle performance Dave Robson.
“Our attention now turns to the test next week followed by a well-earned rest over Christmas before we regroup to tackle the new season.”
Latifi will return for a third season at Williams in 2022, with former Red Bull driver Alex Albon joining the squad in Russell's place.