Lampre-Merida's Nelson Oliveira powered to his maiden Vuelta a Espana stage win on Friday, finishing a minute clear of his closest challengers.

After an early attack fizzled out, Oliveira seized the initiative once again with 22 kilometres to go and never looked back as he held out for victory on the 13th stage from Calatayud to Tarazona.

The top eight in the general classification remained unchanged as a number of contenders sat comfortably in the peloton.

However, Nairo Quintana of Movistar slipped out of the top 10 after struggling with illness in the early part of the stage.

The Colombian did well not to lose time on GC leader Fabio Aru but slipped to 11th overall, behind Gianluca Brambilla and Romain Sicard.

Astana's Aru remains 27 seconds clear of Team Katusha's Joaquim Rodriguez in the standings.

Oliveira made his move, along with Sylvain Chavanel, with 38km to go - attacking from the front of the breakaway on the category-three climb of Alto del Moncayo.

The duo were swiftly reeled in, but - after others tried and failed to make a lead stick - Oliveira tried his luck again, taking sole control of the stage.

The 26-year-old began to build a significant cushion over the chasing pack, while an Astana-led peloton looked unlikely to pose any kind of threat.

Oliveira's advantage was up to 59 seconds as he entered the kast 9km and, despite the best efforts of Team Europcar, all bids to catch him looked destined to end in disappointment.

The lead crept over a minute with 6.5km to go, while Cofidis moved to the front of the chasing group in a bid to close the gap on the runaway leader.

But progress was slow and, roared on by his team from the Lampre car, Oliveira dug deep to maintain his lead, bowing as he approached the finish line.