Sir Mo had fought desperately to claw back the deficit in the finishing straight but Edris held on to win in 13 minutes and 32.79 seconds.
To rub in his victory after years of the Ethiopians being tormented by Farah's brilliance, Edris even gave an impression of his rival's famed "Mobot" celebration as he crossed the line.
In doing so, Edris denied Mo Farah the 10000m and 5000m double that he and the BBC so badly desired.
"After the 10km he was maybe exhausted so he did not have enough for the last kick. I did the Mobot out of respect as well for him".
National champion Kemoy Campbell finished 10th out of the 16 starters in the men's 5000-metre final on the ninth and penultimate day of the 2017 IAAF World Championships in London on Saturday.
He fell several metres behind them going down the back straight. He had also won both distance events in Moscow in 2013.
"Tactically, I was trying to cover every move", said Farah, after being consoled by his wife and four children at trackside.
Into the last 800m however and they ate Tiernan up, though the truth is Farah never looked entirely comfortable: they hit the bell in 12:40.17, and Farah was chasing all the way down the backstretch, unable to get himself in front when he either wanted to or needed to.
Quite simply, Farah will go down in history as Britain's best-ever athlete and one of the greatest the world has ever witnessed. "I got boxed in early on - it doesn't normally happen - but I got boxed in early and couldn't get out".