Alberto Contador (Trek-Segafredo) turned in his most effective climbing performance to date in this year's Vuelta a Espana, blazing a trail through the fog and wet of the steep Los Machucos climb to take second on the stage and strengthen his fifth place overall.
Contador followed a move by Miguel Angel Lopez (Astana Pro Team), the winner of two of the three toughest uphill finishes so far, quickly opening up a gap of around 30 seconds on the favourites group, including race leader Chris Froome (Team Sky).
But whilst Froome struggled slightly, losing time to Vincenzo Nibali (Bahrain-Merida) and Wilco Kelderman (Team Sunweb), a little further up the climb the Spaniard was going from strength to strength, dropping Lopez and slowly but surely gaining time on the last survivor of the day's breakaway, Stefan Denifl (Aqua Blue Sport).
By the summit, Contador had cut back Denifl's margin to 28 seconds, less than a third of the total compared to when he broke away, and had also taken time on all his GC rivals. A top-three finish in his final Grand Tour continues to be possible, then, although there is only one real opportunity remaining - on the Angliru on Saturday - where Contador won in 2008.
"It was a good stage for me, particularly because when I had to push deeper, my legs responded well," Contador said after the stage 17 climb to Los Machucos.
"I knew the right wheel to follow was Lopez, and I had to go with him when he attacked, even though there was a bit of a gap between me and him when he went. At first it wasn't easy to follow his pace, and I actually almost got dropped at one point, but then there came another really steep ramp, I saw he was in a tough place and I didn't think twice about what to do."
Contador's searing uphill attack did not quite net the stage win, and he still has yet to take a victory in his final season, with only three opportunities remaining.
"It was a pity I couldn't do it," he said. "But this has been the day I've felt the best in all three weeks, and I like this rainy weather, too."
The other objective for Contador, of course, is to move ahead on GC, but he argued that it would be extremely difficult to topple any of the riders ahead of him - Froome, Vincenzo NIbali (Bahrain-Merida), Wilco Kelderman (Team Sunweb) and a quietly tenacious Ilnur Zakarin (Katusha-Alpecin), who is still 1:09 ahead of the Spaniard.
"I'm close to the podium and a long way off from it," Contador said. "Today I've got a lot closer. Of course, I'd like to win the race, but I have to be realistic and there are riders and rivals who are very strong ahead of me. Things can always change in a race, but that's going to be very tough."