Ian Boswell pulled off a landmark third place at the Vuelta a Espana but Chris Froome crashed and lost time on a mammoth 11th stage.

The 138-kilometre test was one of the most extreme Grand Tour stages in recent memory, playing out over six categorised climbs and causing dramatic changes on the general classification.

Froome went down during the opening kilometres as the race left Andorra and was forced to battle back over the Collada de Beixalis with the help of his team-mates.

The Brit settled into a rhythm and Team Sky eventually hit the front to set a tempo on the beyond-category Coll de la Gallina. Yet as Astana upped the pace, a bruised and bloodied Froome slipped back and began to lose time on the climb.

With the support of Geraint Thomas and his team-mates Froome continued on, bravely crossing the line eight minutes and 41 seconds down on stage winner Mikel Landa (Astana).

After struggling to put weight on his foot post-stage Froome has gone to the hospital for an x-ray. Cyclingnews reports that an MRI scan in the morning will decide whether he will continue in the race.

Boswell pulled off the best result of his career after covering the early moves and making his way into a breakaway of 19 riders. The relentless barrage of climbs whittled down the group but Boswell hung tough, with the young American finishing 1:40 back on breakaway counterpart Landa in his Grand Tour debut.

Another impressive ride came from Mikel Nieve, who began the final climb in the lead group and set a strong tempo to finish the stage seventh, leading home a number of big names. That result elevated the Basque rider to eighth overall, 1:58 back on new race leader Fabio Aru (Astana).

Froome limited his losses well and holds 15th on the GC, 7:30 off the red jersey. A great show of teamwork also ensured that Team Sky held on to the team GC lead, now with an advantage of 3:45 over Astana.

"All I could do was ride at my own speed after the crash. I'm in quite a lot of pain at the moment. I'm going to get checked up by the medical staff and take it from there," Froome said. "That crash did take quite a lot out of me. From then on I just tried to hang on for dear life. I convinced myself just to get to the finish. My team-mates did a great job to help me stay in the race. It's good to hear that Mikel Nieve and Ian Boswell were up front and it gave me a lot of morale to keep pushing on."  

After the stage Boswell talked TeamSky.com through a memorable stage and put a great personal result into perspective.

He said: "I'm happy with my day but getting back onto the bus it's mixed emotions with Froome and Nico (Roche) losing a bit of time. Our goal today was to see how it played out. On that first climb it was pretty full-on and a group went with quite a few riders we were trying to mark. I just happened to be up there and was able to follow it. From there the gap just went.

"I guess my day was quite different to the rest of the boys as I had (Team Sky Sports Director) Gabba (Rasch) with me up there, talking me through it and remind me to eat and drink - all the basic things. I guess it's still a nice ride. I'm still learning a lot with every breakaway I get into. It's all experience. And really happy with it but at the same time I learned a lot today about ways I could improve in the future."

With the breakaway making it deep into the stage, Boswell admitted it was a surprise when the stage win suddenly became a possibility.

"That's something I wasn't really sure about," he added. "I got to the bottom [of the final climb] and (Sports Director) Dario (Cioni) came up to me and said 'two minutes - race for the stage'. I didn't really expect us to actually stay away, probably until Aru came up to me and then I thought if I could stay with him for a bit I could hang on for a top three. It was a bit surprising in the end - you don't necessarily anticipate that early on. The breakaway won and that doesn't happen very often."

After helping Froome through much of the stage Geraint Thomas told Eurosport: "Froomey obviously had a heavy crash and he said his foot was quite bad. He said his legs were okay but on the especial category climb he started to suffer when Astana really lit it up. He got dropped then, and I was about to get dropped myself anyway so I sat up and waited for him.

"He seemed to come round on the last climb but we just had to keep going. Froomey always keeps fighting and that's what we did. It's unfortunate because obviously Nico was suffering from his crashes as well. Not the ideal day but it was nice to see Boz get up there and get a result for himself."

Picking up after the rest day, the queen stage presented a voyage into the unknown with over 5000 metres of climbing on the agenda.

After a nervous start, Froome's chase back was made more difficult by a fractured peloton. His team-mates came to his aid, with Christian Knees, Vasil Kiryienka and Salvatore Puccio eventually ensuring Froome regained contact on the Coll d'Ordino.

Those same riders were on hand to help control the tempo as the race stabilized, leading the bunch onto the Puerto de la Rabassa.

One climb later things began to split up. Froome slipped back while Nieve dug deep, initially sitting in the group of leader Tom Dumoulin (Giant-Alpecin) before a momentary regrouping and a string of decisive attacks.