Salvodelli is almost cycling royalty after winning the Giro d'Italia this year but he has ridden as a lowly domestique for Armstrong in his pursuit of a seventh consecutive Tour.
However, the 32-year-old Italian got his reward yesterday after joining an early break, powering past Kurt-Asle Arvesen of CSC on a long drag to the finish to join George Hincapie who was victorious at Pla d'Adet on Sunday as a Discovery stage winner.
"It couldn't have gone better than this," Salvodelli said.
"I got on the break because we in Discovery have to get to the front to control the race and then I went with it to win the stage."
Even though he is without a stage victory, Armstrong remains comfortably in control of the yellow jersey, two minutes and 46 seconds ahead of Ivan Basso.
The 239.5 kilometres from Pau to Revel represented the longest stage of the 2005 Tour and its rolling profile, coming immediately after the final mountain stage, meant it was perfect for a long breakaway.
The decisive attack came with just over 55km gone when a 17-rider group was permitted to escape from a peloton less than keen to give pursuit after Tuesday's epic crossing of the Col d'Aubisque.
Armstrong was visibly relaxed as he spent time chatting with fellow riders or joking with the motorbike cameramen.
Ahead, the leading group split again with around 40km to go with eight riders, including Salvodelli and Arvesen, taking the initiative.
Eventually the group was whittled down to a two-man race between Salvodelli and Arvesen. The Norwegian looked like he might take the win when he sprinted clear of the Italian but Salvodelli's superior power took him over the line first.
The victory gave Discovery a significant boost in the team standings and, with their Ukrainian Yaroslav Popovych over six minutes ahead in the young rider competition, Armstrong's last Tour could prove especially sweet for the American outfit.