Colombia's Julian Arredondo climbed to victory on stage two of the Tour de San Luis in Argentina as Phillip Gaimon retained his overall lead of the race.
Arredondo (Trek Factory Racing) escaped from the peloton alongside Peter Stetina (BMC) on the climb to the summit finish at Mirador del Potrero de los Funes and then narrowly defeated his American rival in a sprint to the line.
Nairo Quintana (Movistar) followed three seconds later in third having been one of a small number of riders who counter-attacked unsuccessfully in the final kilometre.
Gaimon crossed the line in what was left of the main bunch in 15th, eight seconds behind Arredondo, and extends his lead in the general classification by 30 seconds to 1min 47sec after second-placed Marc de Maar (UnitedHealthcare) fell away in the closing stages.
Stetina and Arredondo, meanwhile, move up to fourth and fifth place respectively, both 4min 16sec down on Gaimon.
British climber Adam Yates (Orica-GreenEdge) performed well in only his second professional outing, finishing 31 seconds adrift of the winner in 18th. Sprinter Mark Cavendish was ten minutes down in 115th.
Final climb decisive
The 170.6km second stage offered up the first of three summit finishes in the seven-stage race and, predictably, the outcome was decided on the 4.8km final climb.
A five-man escape group was allowed to build up a maximum lead of four and a half minutes, but unlike on stage one, when the peloton failed to catch the breakaway, this time the bunch timed the chase to perfection and swallowed up the last of the escapees 7km from home.
Stetina attacked midway up the climb, but 2013 Tour de Langkawi winner Arredondo was able to follow and had the fresher legs at the death.
Stetina said afterwards: "I decided to attack first. Only Arredondo bridged up to me and I continued to put in the work at the front.
"Arredondo wasn't interested in working. It was a good tactical move on his part, but I wanted to keep the pace high, and the lead group wasn't able to bring us back."
Stage two result
1 Julian Arredondo (Col) Trek Factory Racing, 4:13:21
2 Peter Stetina (USA) BMC Racing, same time
3 Nairo Quintana (Col) Movistar, +3secs
4 Darwin Atapuma (Col) BMC Racing, st
5 Domenico Pozzovivo (Ita) Ag2r-La Mondiale, +5
6 Haimar Zubeldia (Spa) Trek Factory Racing, st
7 Ivan Santaromita (Ita) Orica-GreenEdge, st
8 Damiano Caruso (Ita) Cannondale, +8
9 Miguel Rubiano (Col) Colombia, st
10 Eduardo Sepulveda (Arg) Bretagne-Seche Environnement, st
18 Adam Yates (GB) Orica-GreenEdge, +31
26 Vincenzo Nibali (Ita) Astana, +54
90 Joaquim Rodriguez (Spa) Katusha, +7:06
115 Mark Cavendish (GB) Omega Pharma - Quick-Step, +10:01
1 Phillip Gaimon (USA) Garmin-Sharp, 8:20:34
2 Marc de Maar (Cur) UnitedHealthcare, +1:47
3 Christian Meier (Can) Orica-GreenEdge, +3:56
4 Peter Stetina (USA) BMC, +4:16
5 Julian Arredondo (Col) Trek Factory Racing, same time
6 Darwin Atapuma (Col) BMC, +4:19
7 Nairo Quintana (Col) Movistar, st
8 Haimar Zubeldia (Spa) Trek Factory Racing, +4:21
9 Domenico Pozzovivo (Ita) Ag2r-La Mondiale, st
10 Ivan Santaromita (Ita) Orica-GreenEdge, st
19 Adam Yates (GB) Orica-GreenEdge, +4:47