Olympic road race champion Samuel Sanchez defied intense heat to clinch the toughest stage of the Tour of the Basque Country 2011 for the second year running earlier today.

As temperatures soared on the notoriously difficult Arrate climb, the Euskaltel-Euskadi leader powered a few metres ahead of a group of 11 riders to claim victory on stage four.

Second across the line was Germany's Andreas Klöden of Team RadioShack, with Kazakh Alexandre Vinokourov (Team Astana) third and Team Katusha's race leader Joaquim Rodriguez fourth, all tied on the same time.

After donning a typical Basque txapela (beret) for his win, Sanchez said he was pleased to have taken such a prestigious victory but that failing to dislodge Rodriguez was a major disappointment.

"I didn't feel good on the climb but I was a little more cunning than the rest in what is a very difficult finish," Sanchez told reporters.

"Everybody suffered in that extreme heat, and it made what is already a very tough climb even harder.

"It was great to take that win, but overall the whole race remains completely undecided.

"It's going to be very difficult to beat Rodriguez after he defended himself so well today."

Sanchez said a second victory on the climb, locally famous as a sanctuary for the rare breed of Azpi Gorri shaggy goats, was "another highpoint" in his career.

Rodriguez said that despite holding the lead after Arrate, his chances of keeping it on Saturday's decisive individual 24 kilometer time trial were slim.

"There are a lot of real time trial specialists here and a lot of them are just a few seconds behind me overall," Rodriguez told reporters after crossing the finish line.

"I just didn't have the legs today to make an all-out attack and try to get some time on them," Rodriguez added and continued "The heat was really bad, but it's the same for everybody."

"I expect that tomorrow (Friday) will be won by a breakaway, all the favourites will be pretty tired after today and want to recover as best they can for the final time trial."

Team Saxo Bank-SunGard's lead climber Chris Anker Sørensen won the sprint in the chase group, but was unable to stay with the group of riders that featured today's stage winner Sanchez.

"The team did a terrific job putting me in a good position before the final climb and for a long time I was really on the edge. At the time when Vino (Vinokourov) makes his move, I was in no condition to answer so I had to just find my own rhythm and only lost about 30 seconds, Sørensen told Roadcycling.com and Roadcycling.mobi.

"In this company of riders, it's actually a pretty good result for me and I even dropped some world class climbers as well. However, I still need the last little bit of punch in order to follow but there's still some time before the Ardennes Classics where I hope to get a chance to go on my own," Sørensen concluded.

The Volta Ciclista al Pais Vasco 2011 finishes with an individual time trial on Saturday in the city of Zalla.

Watch Tour of the Basque Country 2011 video highlights in our Roadcycling.com videos section.

Click here for complete stage 4 results.