The indications from the opening days of the Giro d’Italia in Italy's deep south have been heartening for Vincenzo Nibali and his Astana team.

While Sky's collective power remains largely unchallenged, the terse climbs and winding descents in Campania and Calabria exposed crevices in the Sky breastplate that will no doubt be tested further as the race moves north and subsequently enters the Dolomites.

"The Giro d'Italia has always been like this. There are always lots of nervous stages and on days like these, controlling things with your team is a lot more difficult," Nibali told Cyclingnews.com  "There's a bit of confusion in the finale and you have some pretty fast riders in there, too, who are racing for the sprint finish and it all becomes quite complicated. Then when you throw in a bit of rain in the finale over roads that aren't exactly the widest, well, that just makes it all a bit more difficult again."

On Wednesday, Italian sports daily, Gazzetta dello Sport, speculated that mutiny might be brewing inside the Sky team as Uran and Henao were, according to the paper, chasing a stage win on Tuesday rather than working to protect team leader Wiggins.

"I don't know what to say about that," Nibali said. "Of course, I read about it but I've also heard that Bradley told them to go on and try to win the sprint for the stage, so honestly, I don't really know what went on at Sky. All I can say is that these are very difficult finishes and it's very complicated for everyone to stay together because everything happens so quickly."

Nibali himself had suffered a troublesome moment on stage four when he had a flat on the approach to the final climb, the Croce Ferrata, but his teammate Valerio Agnoli instantly handed over his wheel and Nibali was securely in the group of favourites by the time Sky began enforcing their rhythm.

"We saw that the weather wasn't great, the descent was slippery and there wasn't long left to the finish but Agnoli gave me his wheel immediately and I was able to get back on almost straightaway," Nibali said.

Saturday's central 55 km time trial is expected to separate the overall contenders by minutes rather than seconds, but Nibali is confident about his chances of curbing his losses to Wiggins. "The route is really very difficult," he said. "The important thing for me is going to be getting there with the most amount of energy possible and then perform well time trial."