Bradley Wiggins held on to the race lead on stage 13 of the Vuelta a Espana after fending off a number of attacks from his main rivals.
Five categorised climbs saw the Brit and Team Sky tested to the limit as attacks from rival riders began as soon as the racing got under way in Sarria.
Wiggins finished to the fore in a depleted peloton, one minute and 33 seconds back after 4600 metres of climbing across the stage, holding on to the red leader’s jersey as a breakaway was allowed to contest the win.
Rival Vincenzo Nibali (Liquigas) scooped an early six-second time bonus at the first intermediate sprint of the day and as a result moved up to second place overall, four seconds back on Wiggins.
Chris Froome once again played a key role in fending off dangerous attacks but was able to finish comfortably inside the same group as the favourites and now sits third, still seven seconds back.
The team had the unenviable task of controlling the race as attacks began on the very first climb of the day, rising to the challenge to support the red jersey in numbers and check off another potentially crucial stage following a tense chase off the Puerto de Ancares.
At the finish it was Michael Albasini who sprinted to victory on the day after solid work from the day’s breakaway allowed a 20-man collective to contest the stage win.
The Swiss HTC-Highroad rider kicked early on the finishing straight and held off the attentions of Eros Capecchi (Liquigas) and Daniel Moreno (Katusha) to take an impressive victory in Ponferrada.
Wiggins crossed the line shortly after and was philosophical about the slight time loss, saying: "I'm pretty relaxed about how things went today and it was another good performance from the team.
"Yes, Nibali made up six seconds by attacking on that first descent and winning the sprint, but I didn't see the point in wasting energy unnecessarily and taking big risks just to try and defend a few seconds.
"Fair credit to him for having a go, but I don't think the race will have been won or lost today - the time gains or losses in the mountains days to come are going play a much bigger role in how this race is decided.
"I'm really happy to still be in the jersey though, and it's a huge honour to be able to pull it on each morning and as I've said before, we'll be doing all we can to defend it to Madrid."
There was a lot of tension ahead of a stage that was always likely to be crucial with a number of climbs to negotiate on the first of a tough trilogy of mountain stages.
It did not take long for the fireworks to begin following the opening third category Alto O’ Pico da Pena where, with a sprint point at the foot of the descent, it was no surprise to see Nibali come to the fore and scoop up valuable bonus seconds.
The effort caused an elite selection to form as 33 riders broke clear including Nibali and Wiggins, the first of a number of moves that characterised the opening stages.
After some scrambling in the bunch and a chase led by Astana things came back together, adding up to a frantic start all before the race had even hit the 35km mark en route to a rapid first hour.
Nicolas Roche (Ag2r) proved to be among the most determined riders on the day, finally making his way into a successful move at the third time of asking – a 28-man break which was finally allowed to stick after being driven on by Euskaltel.
David Moncoutie (Cofidis) was an ever-present on the climbs throughout the day and moved into the mountains classification jersey as a result after a long day in the breaks.
Team Sky controlled the pace on the focal point of the day, the first category Puerto de Ancares where Joaquim Rodriguez (Katusha) became one of the first big names to attack, drawing a reaction from a number of the favourites.
The descent that followed saw plenty of action as Fredrik Kessiakoff (Astana) pushed the pace on the way back down the mountain, dragging with him a dangerous group including Nibali, Bauke Mollema (Rabobank) and Jakob Fuglsang (Leopard Trek).
Thomas Löfkvist, Chris Froome and Xabier Zandio set to work to drag back the move as a tense chase developed on the descent before the juncture was finally made with 44km remaining.
As the terrain flattened out it was clear the break would be able to stay clear, allowing the likes of Roche, Chris Anker Sorensen (Saxo Bank) and Moreno to all move towards the top 10, the latter actually sneaking into ninth after the dust had settled courtesy of some aggressive riding.
After the stage Sports Director Steven de Jongh was in no doubt that the stage had been a brutal one for all involved, but was happy to see the team step up to the plate.
He said: “It was one of the toughest days for everyone. It was a lot of work but the guys defended the jersey well. Nibali took back a few seconds but it was a good day all in all.
“With the two cat three climbs at the start there were a lot of guys who wanted to go away in the breakaway. They might not have been interested in the stage win but with the bonuses they were all fighting to be in there. Nibali was up there and at one point Brad was in there too. It was tough racing.
“It was good to see the guys on the front up the climbs. It was a really impressive performance from the team. On the way back down the Ancares it was not that much of an issue. A couple of guys got away on the descent but I think the guys handled it well.”
With another tough stage negotiated and the fight at the top of the standings closer than ever before, de Jongh is under no illusions that the twin mountaintop finishes at the weekend will be key.
“The weekend is going to be really important - decisive actually. The mountaintop finishes on Saturday on Sunday should blow the race open,” he added.