Chris Froome moved up to second place at the Vuelta a Espana after another day of high drama in northern Spain.
Froome matched biggest rival Alberto Contador (Saxo Bank-Tinkoff) blow for blow on the final climb up to the Estación de Valdezcaray, and the duo were both part of a sizeable group which crossed the line 1min 04sec down on Simon Clarke (Orica-GreenEdge), who had outsprinted breakaway accomplice Tony Martin (Omega Pharma-Quick Step) to take the stage win.
Joaquim Rodríguez (Katusha) was also in that group of favourites, and took control of the red jersey with a one-second margin over Froome. Contador now sits four seconds further adrift in third, and an equally-assured climbing display from Rigoberto Urán saw him move up to sixth place overall, just 11 seconds off the pace.
The day’s big loser was overnight leader Alejandro Valverde though, the Movistar man getting caught up in a crash 29km from home and eventually crossing the line 55 seconds down on Rodriguez, Contador and Froome.
The fourth stage had begun predictably enough with Clarke and Martin forming part of a five-man break that moved clear almost as soon as the start flag had been lowered.
The peloton initially seemed happy enough to let them go, and their lead had stretched to over 13 minutes before Team Sky decided to step up the chase 30km from home.
It was around that time that the crosswinds began to whip up, and when Juan Antonio Flecha put the hammer down on the front, the ramifications behind caused a large tumble which involved Valverde and several of his team-mates.
With Team Sky, BMC and RadioShack having no choice but to press on if they were going to catch the break, the peloton was split into pieces behind, with several echelons fanning right across the road.
Those groups would merge into three as they began the final climb of the day, but by that time it was becoming clear that the breakaway were going to have their day in the sun.
As the road ramped up, Clarke and Martin made their move and instantly shed their rivals as they pressed on towards the summit. The duo remained clear as they sprinted it out for the line, with Clarke ultimately edging the German by a two-second margin.
The real drama was taking place behind though, and Froome and Contador were still a minute clear of Valverde as they began the 13km drag to the summit.
Marking each other closely, the duo temporarily moved clear with Nicolas Roche (AG2R) before being hauled back in the final 2km by a group of 22 riders including the industrious Rodríguez.
From then on the pack stayed together, with Sergio Henao pacing Froome to the line in 14th place. Valverde trailed home less than a minute adrift, but those losses saw him drop to ninth place in the overall standings.
After the stage, Sports Director Marcus Ljungqvist defended the team's decision not to wait after Valverde had fallen, and insisted there was no malice whatsoever in their judgement.
He said: "We haven’t seen a replay of the crash yet but let’s be clear, we are not the type of team who would ever try to benefit from some else’s misfortune, and there is always two sides to the story.
"It was clear that the peloton was nervous because of the crosswinds, and it was only a matter of time before one team hit the front. We took that responsibility because it was vital Froomey was well positioned, and then unfortunately the crash came soon after that.
"There’s always a lot of confusion straight after a fall and it takes time to know who’s been affected, and who’s been held up behind. Before we knew Valverde was down we were already 50 seconds in front and we had to keep chasing the break before the last climb of the day.
"It’s really unfortunate that it was the race leader who was caught up, but we didn’t have any choice but to keep going by the time we found out because there were other teams riding hard as well.
"As for Froomey, he showed he was really strong again and that was good to see. That last climb was the toughest of the tour, but he handled himself really well and is in a really good position on the GC."
Stage 4 result
1. Simon Clarke (Aus) Orica - GreenEdge 4:30:26
2. Tony Martin (Ger) Omega Pharma-Quickstep 0:00:02
3. Assan Bazayev (Kaz) Astana Pro Team 0:00:22
4. Marcos Garcia (Spa) Caja Rural 0:00:55
5. Nicolas Roche (Irl) AG2R La Mondiale
6. Linus Gerdemann (Ger) Radioshack-Nissan 0:00:57
7. Laurens Ten Dam (Ned) Rabobank Cycling Team
8. Andrey Zeits (Kaz) Astana Pro Team 0:01:01
9. Bauke Mollema (Ned) Rabobank Cycling Team 0:01:04
10. Jan Bakelants (Bel) Radioshack-Nissan
General classification after stage 4
1. Joaquim Rodriguez Oliver (Spa) Katusha Team 13:18:45
2. Christopher Froome (GBr) Sky Procycling 0:00:01
3. Alberto Contador Velasco (Spa) Saxo Bank - Tinkoff Bank 0:00:05
4. Bauke Mollema (Ned) Rabobank Cycling Team 0:00:09
5. Robert Gesink (Ned) Rabobank Cycling Team
6. Rigoberto Uran Uran (Col) Sky Procycling 0:00:11
7. Daniel Moreno Fernandez (Spa) Katusha Team 0:00:14
8. Nicolas Roche (Irl) AG2R La Mondiale 0:00:24
9. Laurens Ten Dam (Ned) Rabobank Cycling Team 0:00:46
10. Juan Jose Cobo Acebo (Spa) Movistar Team 0:00:47