Richie Porte rode a calculated ninth stage of the Giro d'Italia to track his main rivals and put further time into those behind.

The Tasmanian looked cool under pressure as he again found himself clear up the road in an elite group of favourites on the run into San Giorgio del Sannio.

The front group split up on the final climb of the stage after a burst from Fabio Aru saw Porte push on alongside the Italian, race leader Alberto Contador (Tinkoff-Saxo) and Aru's Astana team-mate Mikel Landa.

Happy to sit on the back of the quartet and be dragged along, Porte measured his efforts to come home on the wheel of the maglia rosa, maintaining his third position at 22 seconds back ahead of the first rest day.

Aru sprinted ahead to take a single second out of the pair, with barely anything to separate the three riders since the opening team time trial.

Porte was well-supported once again by his Team Sky team-mates, with Leopold Konig and Mikel Nieve finishing in a chase group 46 seconds back. Vasil Kiryienka towed his team leader right onto the wheel of Aru on the Passo Serra shortly before his attack.

A gruelling parcours and a big breakaway ensured that Elia Viviani held on to the red points jersey ahead of the next sprint day on Tuesday.

“Today’s stage went really well, I’m happy it is over, it’s nice to be into the racing, I feel good and looking forward to a good rest day,” Porte said.

"Yes, but also you see like today, you have to take the opportunities where they come," he said when asked whether he was waiting for the time trial."

Until now, Sky have been very discrete.

“It’s been a very good nine stages for us, a stage win - very good - we’ve got the red jersey and we’ve come here to play the long game," team principal Dave Brailsford said. “From experience we came into this Grand Tour maybe thinking about it slightly differently to others, biding our time and being a bit more patient and strategic and using the fact that Astana and Tinkoff-Saxo are very strong and we can ride off that for the time being.

“As that time trial is looming, you’ve got to think about it. But you’ve got to be careful it doesn’t start to cloud your thinking. From our point of view we’ll just take it on the stage by stage and bide our time and ultimately.

“There haven’t been any significant time differences yet, but we do know that there will be then in the time trial, positive or negative. That’s going to happen. How, though, we don’t know yet.”

“You can’t rule Rigo out, it’s quite clear that he’s been ill and if he gets back to his full potential - and he’s got quite a while to do that - he could put minutes, literally, into people at that time trial.”