Julian Arredondo rode clear of the breakaway during Stage 18 of the Giro d'Italia to claim the biggest win of his career.
Arredondo crossed the finish line 17 seconds ahead of Fabio Duarte to take his first Grand Tour win.
After taking maximum points in the first two climbs of the stage today, the Colombian has all but won the King of the Mountains classification which he has held since stage eight.
With four kilometres to go Arredondo attacked the breakaway group and with a surge of pace which no one could follow he found himself crossing the line on his own.
Arredondo praised his coach, Josu Larrazabal, for helping him achieve the victory.
The 25-year-old said, according to Sky Sports: "I didn't imagine for a moment that today could be my day. My coach, Josu Larrazabal, believed in me.
"At the foot of the final climb, I wanted to attack, but Josu said, 'Take it easy, not yet'.
"Then, much higher up, he said, 'Julián, now!' So I won the stage because of his advice. He gave me the calm and the patience, and the day ended perfectly for me. I dedicate this stage win to him."
Nairo Quintana remains in control of the pink jersey after finishing just ahead of second placed Rigoberto Uran, meaning his lead is still one minute 41 seconds.
Cadel Evans lost valuable time today and dropped from third place to ninth. Pierre Rolland takes his place on the bottom of the podium, three minutes 29 seconds down on Quintana.
Stage 18 result
1 Julian Arredondo (Col) Trek Factory Racing, 4:49:51
2 Fabio Duarte (Col) Colombia, +17secs
3 Philip Deignan (Ire) Team Sky, +37
4 Franco Pellizotti (Ita) Androni Giocattoli-Venezuela, +1:20
5 Edoardo Zardini (Ita) Bardiani-CSF, +1:24
6 Thomas de Gendt (Bel) Omega Pharma – Quick-Step, +1:38
7 Ivan Basso (Ita) Cannondale, +1:43
8 Dario Cataldo (Ita) Team Sky, +1:59
9 Fabio Aru (Ita) Astana, +2:43
10 Nairo Quintana (Col) Movistar, +2:46
1 Nairo Quintana (Col) Movistar, 77:58:08
2 Rigoberto Uran (Col) Omega Pharma – Quick-Step, +1:41
3 4 Pierre Rolland (Fra) Europcar, +3:29
4 Fabio Aru (Ita) Astana, +3:31
5 Rafal Majka (Pol) Tinkoff-Saxo, +3:31
6 Domenico Pozzovivo (Ita) Ag2r-La Mondiale, +3:52
7 Ryder Hesjedal (Can) Garmin-Sharp, +4:32
8 Wilco Kelderman (Ned) Belkin, +4:37
9 Cadel Evans (Aus) BMC, +4:59
10 Robert Kiserlovski (Ned) Trek Factory Racing, +8:33