Vinokourov finished the 33 1/2-mile individual time trial in one hour, six minutes and 34 seconds, rolling past Cadel Evans of Australia by one minute, 14 seconds. German Andreas Kloeden finished third despite losing control of his bike on the wet road midway through his run. Andrey Kashechkin of Kazakhstan and Englishman Bradley Wiggins were fourth and fifth respectively.
"For me the tour really began today," said Vinokourov. "I am confident in my team and I'm looking forward to the next mountain range. I think we can still win the tour, it'll be very difficult but we'll try our best."
Rasmussen finished in 11th place Saturday, keeping his overall lead, though it was trimmed to just one minute with Evans finishing in second place in Stage 13.
Levi Leipheimer is still the top American, moving up to fifth place and 3:37 behind Rasmussen.
The 20-stage race covers more than 2,200 miles and will wind up July 29 along the Champs-Elysees in Paris.