The Colombian, winner of the 2014 Giro d'Italia, left behind cycling's grand tour stars during a lethal attack in the final five kilometres up to Monte Terminillo ski station.
Now, with only two days to go, including the final 10-kilometre time trial on Tuesday, Quintana appears to have his comeback race in the bag. If so, it would mark a successful return to competition after crashing in the national championships and skipping the Ruta del Sol, where Sky's Chris Froome won a head-to-head battle with Alberto Contador (Tinkoff-Saxo).
"Of course, miracles exist!" Quintana said. "I work, with good preparation behind me and a great team that always takes care of me."
Quintana is building towards the Tour de France again after placing second behind Froome in 2013. The 25-year-old last year won the Giro d'Italia and aimed at the Vuelta a España, where a crash in the time trial forced him to abandon.
He began this year in South America, headlining Argentina's Tour de San Luis in January. But another crash in the final of the Colombian championships on February 8, landing on the same shoulder he fractured in the Vuelta, forced him to delay his return to Europe and to miss the Ruta del Sol. He only arrived from Colombia four days before the Tirreno-Adriatico began.
"I trained hard in Colombia to be ready for Tirreno-Adriatico. In the first days, I suffered because of my lack of race rhythm, but I'm now good," he said.
"I had a hard season last year after my fall in the Vuelta and my fractured shoulder. It took me time to recover, and there is still some pain. The fall in the national championships left me sad because I couldn't compete in Andalucía. But thanks to the support of my family, my wife and daughter, I came through it, got back into shape."
At the Tirreno-Adriatico, Quintana blasted away from his rivals and further distanced former leader, Sky's Dutchman Wout Poels. Near the top, snow fell hard on the six-foot-one Colombian who put 41 seconds into Bauke Mollema (Trek Factory Racing) and 55 into a group with Contador and Brit Adam Yates (Orica-GreenEDGE). He leads the overall by 39 seconds over Mollema.
It was not the first time Quintana has run away with the win under snow. In last year's Giro, he rode free over the Passo dello Stelvio and took the stage win and overall leader's pink jersey on the next climb to Val Martello. He never let it go and became the first Colombian to win in the race's history.
“In Colombia, I live at an altitude of nearly 3000 metres. Some mornings it is very cold, four or five degrees, and it can go down to zero. At altitude, it’s a different cold, but then, racing in Europe, we get used to even more extreme conditions,” he added. “When you are a leader, you have to have a strong head and legs, whatever the weather.”
If Quintana holds on, he will also become the first Colombian to win the Tirreno-Adriatico in its 50 years.
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