The Euskadi–Murias rider attacked 25 kilometres from the finish of the 180km route from Saint Palais to Urdax, and held off the chasing pack to secure a surprise win.

Iturria looked to have dropped from contention before surging back to outlast his fellow breakaway riders.

He appeared vulnerable around 1km from the conclusion of the stage, but the chasers were unable to coordinate their response effectively and the 27-year-old took full advantage.

He crossed the line in four hours 36min 44sec to beat fellow Spaniard Jonathan Lastra and American Lawson Craddock.

Slovenian Primož Roglič comfortably retained the red jersey after leading home the peleton, which completed the stage over 18 minutes after Iturria.

Roglič remains 1min 52sec ahead of Alejandro Valverde of Movistar in second.

Colombia's Miguel Ángel López of Astana remains in third place heading into tomorrow's 12th stage, a flat 174.1km journey from Navarra Circuit to Bilbao.