"Today was the first of three chances we get to take back 3 seconds. We tried today to make it as hard as we could, and Dumoulin showed he was strong enough. Tomorrow we try again."

Those were the words of Astana's Dario Cataldo after stage eighteen at the Vuelta a España. The stage did not finish uphill, but held enough climbing to classify as a day in the mountains.

Strong work by Astana Pro Team to hold a high speed at the front of the elite group of leaders changed little but showed much. Fabio Aru remains second in overall classification, 3 seconds behind Tom Dumoulin of the Netherlands.

All day Thursday Astana and Aru worked on the Dutch rider, attacking at every opportunity, every time the road turned uphill. Dumoulin held the attacks but rode defensively on a final 10km climb with an average gradient of less than 6 percent.

Saturday's final mountain stage features four first-category climbs, with some pitches as steep as 11 percent.

“I tried my best, and I wanted to isolate Dumoulin and put him in difficulties. The team collectively rode very well today," Aru said. “Today was maybe not the best day to try it, the third of these mountain stages is the hardest. And three seconds is nothing.”