Simon Gerrans became the sixth Australian to pull on the yellow jersey after Phil Anderson, Stuart O'Grady, Brad McGee, Robbie McEwen and Cadel Evans.
“This is a dream come true, it really is. Yesterday I was able to win the stage off the back of a fantastic team effort and today we really showed how close we are as a team with how well we worked together," said Gerrans.
"At the end of the day we come out with this stage win and, to top it all off, this yellow jersey. It doesn't get much better than that."
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The Australian-based squad, racing in only its second Tour, finished a single second ahead of ahead of Omega Pharma-QuickStep in a time of 25min 56sec to claim back-to-back wins. Team Sky finished third at four seconds enhancing the chances of its team leader Chris Froome.
Saxo-Tinkoff finished in fourth place, nine seconds behind Orica-GreenEDGE, to keep the hopes of Alberto Contador alive
The short 25km team time trial was a flat route finishing on the city's famous Promenade des Anglais waterfront.
Gerrans, Michael Albasini, Simon Clarke, Matt Goss, Daryl Impey, Brett Lancaster, Cameron Meyer, Stuart O'Grady and Svein Tuft, who were the 18th group of riders to leave the start gate, stayed close to Omega Pharma QuickStep at the mid point time check and motored home to win by the narrowest of margins.
“I don't think there was one particular point on the course where we won today or one particular thing that we did but we just worked fantastically together as a team," said Gerrans.
"We're such a close group of guys, we're all such good friends, and I think that really shows in a teams time trial. Everyone was really committed to it and gave one-hundred per cent and it came out in the results."
Gerrans now leads teammate Daryl Impey and Michael Albasini in the general classification ahead of Wednesday's fifth stage.
“One thing I said last night when I was thanking all the guys for their help was that the big thing I achieved yesterday was that I opened the floodgates," said Gerrans. "
"I got that first win [at the Tour de France] under the belt for Orica-GreenEDGE and I think the first one is always the hardest one to get. I was sure they were going to come thick and fast after that but never in our wildest dreams did we think it would come already today."
Stage five is a 219km ride from Cagnes-sur-Mer to Marseille in which the sprinters are expected to dominate.
SBS will broadcast all stages of the Tour de France live.
