The gruelling 784km (416km timed) trek from Bolivia's salt flats at Uyuni to Iquique led to a host of high-profile contenders for the 2015 title limping out, including 2014’s runner-up Jordi Viladoms.
While Honda's Spanish rider Barreda, who led the standings by more than six minutes overnight, is still riding his chance of glory went up in smoke as he lost almost 90 minutes.
The bikes classification is now led by 2014’s winner Marc Coma, second going into Monday's ride which was a rest day for the cars contingent.
The Spanish four-times Dakar winner riding a KTM finished ninth behind Quintanilla to lead overall by more than nine minutes from Paulo Goncalves.
The 38-year-old Spaniard admitted the stage had been extremely gruelling.
"It was a very extreme day," said Coma. "It was too difficult on the salt lake, there was the altitude, the cold, everything mixed in.
JUST 11 SEC GAVE QUINTANILLA THE STAGE
Three other high-profile motorcycle contenders whose race ended prematurely on Monday were Michael Metge, Alessandro Botturi and Daniel Gouet.
KTM's Chilean rider Quintanilla was celebrating his first stage win, made all the sweeter as it came on home turf. He moved up a place into third overall, almost 30 minutes behind Coma.
He took the stage by a mere 11sec from Juan Pedrero Garcia, with Slovakia's Stefan Svitko another second back in third.
FEMALE RIDER CHALLENGING FOR LEAD
Fourth was Australian Dakar first-timer Toby Price, only 41sec behind the stage winner, and in fifth Laia Sanz, who is edging closer to being the first woman to win a motorcycle stage on the event described as “motorsport's Everest”.
"Today was a really hard day," Sanz confessed. “At the beginning some riders didn't want to start because it was dangerous and cold but in the end for me it was a good stage.
“I'm very happy with this fifth position," added the 29-year-old, who first competed in the Dakar in 2011.
Monday was a rest day for the car category which Qatari veteran Nasser al-Attiyah leads.
Take a look at Monday's motorcycle action.
Stage 8 - Bike/Quad - Stage Summary - (Uyuni... by Dakar