Italy's Trentin, riding for Quick-Step Floors, was part of a 15-man break which emerged on the 164.8 kilometre route from Caravaca de la Cruz to El Pozo Alimentación.

Trentin triumphed in 3 hours 34mins 56sec to win his second stage of the Grand Tour, following his victory on stage three.

He raced past Spain's Movistar rider Jose Joaquin Rojas, who finished one second behind, and sits in the green jersey as points lader.

Jaime Roson Garcia, another Spaniard, came home third for Caja Rural, 19 seconds adrift.

"I really wanted it," said Trentin to reporters afterwards.

"I was thinking about this stage for a while because the climb was hard, but it was a steady grind."

Team Sky rider Froome retained his 36-second lead overall in front of Colombia's Orica-Scott cyclist Estenan Chaves.

Nicolas Roche of Ireland, racing for BMC, made up ground on the second-place rider and now boasts the same time as the Colombian.

The 11th stage tomorrow is a 187.5km route from Lorca to Calar Alto Observatory.

Froome is hoping to become just the third person to win the Vuelta and Tour de France in the same year.