Tarazona - Portugal's Nelson Oliveira came home alone to land the 13th stage of Spain's Vuelta on Friday with Fabio Aru retaining the overall leader's red jersey.
For Lampre rider Oliveira, a three-time national time-trial champion, this was a first ever stage win on one of the Grand Tours.
He set up his personal milestone by attacking with 30 kilometres of the 178km ride from Calatayud to Tarazona remaining. He had his fellow members of a breakaway group in trouble on the final climb of the day, extending his lead to the line.
France's Julien Simon (Cofidis) out-sprinted Ireland's Nicolas Roche (Team Sky) for second, this pair chased home by the rest of the breakaway group.
"It was a difficult day but things worked out in the best way possible for me," reflected Oliveira in an interview with Spain's public television station.
"It's my first international victory and the first on a Grand Tour," he added.
"Those last 30km were the longest of my life."
Italian Aru took 36th place to keep the overall lead by 27 seconds from Katusha's Joaquim Rodriguez. Tom Dumoulin is third, a further three seconds away.
Saturday's 14th stage is the longest of the 2015 Vuelta, a 215km mountainous ride from Vitoria to the ski station of Alto Campoo, with an hors-category summit finish.
Results from the 13th stage of Spain's Vuelta, a 178.0km ride from Calatayud to Tarazona on Friday:
1. Nelson Oliveira (POR/LAM) 4hr14min 01sec, 2. Julien Simon (FRA/COF) at 1:00, 3. Nicolas Roche (IRL/SKY) 1:00., 4. Sylvain Chavanel (FRA/IAM) 1:00., 5. Jose Joaquin Rojas (ESP/MOV) 1:00., 6. Rinaldo Nocentini (ITA/ALM) 1:00., 7. Kevin Reza (FRA/FDJ) 1:00., 8. Mickal Cherel (FRA/ALM) 1:00., 9. Cameron Meyer (AUS/ORI) 1:00., 10. Maxime Monfort (BEL/LOT) 1:00., 11. Valerio Conti (ITA/LAM) 1:00., 12. Pawel Poljanski (POL/TIN) 1:00., 13. Gianluca Brambilla (ITA/ETI) 1:00., 14. Alessandro De Marchi (ITA/BMC) 1:00., 15. Ruben Plaza (ESP/LAM) 1:00., 16. Romain Sicard (FRA/EUC) 1:00., 17. Niki Terpstra (NED/ETI) 1:00., 18. Jerome Coppel (FRA/IAM) 1:00., 19. Stephen Cummings (GBR/MTN) 1:00., 20. Kenny Elissonde (FRA/FDJ) 1:00.
32. Alejandro Valverde (ESP/MOV) 4:48., 36. Fabio Aru (ITA/AST) 4:48., 38. Joaquin Rodriguez (ESP/KAT) 4:48., 41. Tom Dumoulin (NED/GIA) 4:48.
1. Fabio Aru (ITA/AST) 51hr 33min 19sec, 2. Joaquin Rodriguez (ESP/KAT) at 0:27., 3. Tom Dumoulin (NED/GIA) 0:30., 4. Rafal Majka (POL/TIN) 1:28., 5. Esteban Chaves (COL/ORI) 1:29., 6. Alejandro Valverde (ESP/MOV) 1:52., 7. Daniel Moreno (ESP/KAT) 1:54., 8. Mikel Nieve (ESP/SKY) 1:58., 9. Gianluca Brambilla (ITA/ETI) 2:51., 10. Romain Sicard (FRA/EUC) 2:51., 11. Nairo Quintana (COL/MOV) 3:07., 12. Louis Meintjies (RSA/MTN) 4:15., 13. Domenico Pozzovivo (ITA/ALM) 5:19., 14. Fabrice Jeandesboz (FRA/EUC) 7:29., 15. Kenny Elissonde (FRA/FDJ) 7:46., 16. Nicolas Roche (IRL/SKY) 9:38., 17. Bart De Clercq (BEL/LOT) 9:50., 18. Andre Cardoso (POR/CAN) 10:19., 19. Stephane Rossetto (FRA/COF) 10:49., 20. Samuel Sanchez (ESP/BMC) 11:07.