Vincenzo Nibali (Astana), after winning the stage 18 mountain time trial and adding more time to his overall lead, underscored the Giro d’Italia’s complications so far. Talking about Bradley Wiggins (Sky), he said the race is more difficult than the Tour de France.

“The Tour has long and straight roads, only one stage [into Switzerland] was difficult with narrow roads and turns. Here, however, was truly hard starting from the first week,” Nibali said on live TV.

He said he took his chances to try to distance Wiggins when the weather turned worse. On the stage to Pescara at the end of the first week, Nibali attacked on a wet descent. Wiggins crashed and lost 1-24 minutes.

“That’s the Giro; it comes earlier in the year with bad weather… With rain and cold temperatures, everything changes. Last year in the Tour, it never rained. I was unlucky only in one stage because I had a muscle problem. I preferred to sit up, wait and keep a cool head until the finish. In fact, I only lost 20 seconds that day.”

Nibali finished the 2012 Tour de France third overall at six minutes and 19 seconds behind Wiggins. After his win in the wet time trial up to Polsa, he leads the Giro d’Italia by 4-02 minutes over Cadel Evans (BMC Racing).

Wiggins abandoned the Giro d’Italia after stage 12 to Treviso. He suffered from a chest infection and had already lost five minutes to Nibali.

“He would’ve done well in this time trial, but we know how hard the Giro is. How many dangers there are,” Nibali added.

“Given how he raced in the Tour last year, I knew I had to battle him every time I found some ground to do so… I had a good margin on him, but had he stayed it would have been a fight to the last moment.”

Nibali seems the probable Giro winner with snow likely forcing modifications to the final two mountain stages. He already placed third overall and won the Spanish Grand Tour, the Vuelta a España in 2010.

He will skip the Tour de France this year and focus on the World Championships. Wiggins is due to return to support Sky team-mate Chris Froome in the Tour.