* Contador powers to time trial victory
* Extends overall lead to nearly five minutes
Spain's Alberto Contador strengthened his overall lead in the Giro d'Italia with his second stage victory of the race, a 12.7 kilometre uphill time trial, on Tuesday.
Contador won the stage from Belluno to Nevegal with an advantage of 34 seconds over Vincenzo Nibali of Italy with Italian Michele Scarponi in third.
After winning stage nine on Mount Etna and taking the lead, stage 16 was Contador's second victory and he now leads overall by four minutes 58 seconds from Scarponi with Nibali in third.
Nibali claimed the fastest time on the flatter first five kilometres of the course, but Contador's steadier ascent on the second section enabled the Spaniard to surge ahead.
"The Italian fans were a big help psychologically today, they cheered me just as much they would any local rider," Contador said.
"They've really been supportive for the last three weeks, and for any rider that's always a big plus."
Nibali was left in awe of 2008 Giro winner Contador's display.
"Beating Contador today would have been impossible, it was like racing against a Martian."
"Alberto is the strongest I've seen him in years," added Stefano Garzelli, who took fifth on the stage.
"We all knew he'd be a contender but he's on another level altogether."
Contador's major remaining challenges are two summit finishes in the Alps on Friday and Saturday, and a final flat time trial on May 29 through the streets of Milan where the race ends.