The Giro d’Italia may be wearing the new mantle.

Ivan Basso, riding with his characteristic smile and/or grimace but with the methodical power and grace of a mountain lion on the attack, took the agonizingly steep but incomparably thrilling Monte Zoncolan, the 15th stage of the Giro — vaulting him into third place in the general classification and more than a minute ahead of his closest rival, Cadel Evans.

Spaniard David Arroyo maintained the leader’s pink jersey, but lost more than three minutes to Basso. Tomorrow’s rest day will prove a temporary respite from mountain pain over the final week of the Giro.

For a time Evans managed to duke it out with Basso. But Cadel was out of the saddle much of the time, expending precious upper-body strength while Basso simply ground out the gears in his saddle up the relentless grade.

The middle 6 kilometers of the climb — the day’s fourth — averaged 15 percent — which any cyclist who pays attention to such things knows is a world of hurt just over a few hundred feet. There were 22 percent pitches on the final 3 kilometers. To see world champion cyclists pedaling with the cadence and fatigue of weekend riders climbing was quite a sight. You don’t normally find that kind of suffering, even in the Tour de France.

It may be proof that the post-doping era has finally taken root in the Giro, because the slumped shoulders and saliva ropes and sunken cheeks and vacant expressions of the final climb testified to real sacrifice. During the height of the doping era riders would show hardly any signs of true suffering, and there was always the sense that their physical limits had less to do with god-given genetics than whether they were juiced that particular day.

Among the top three favorites of this year’s Giro, Evans is the only rider with unimpeachable credentials. Basso and Alexander Vinokourov both have been banned from the sport — and now returned — after testing positive. Evans has maintained from the beginning he was never part of the doping circle of cycling, and his results have never given any reason to doubt.

So far this year’s Giro has been “clean” (full testing cannot be completed till after the race is over), in contrast to the Landis-Lance eruptions going on over in the U.S. Let’s hope the Italian classic stays that way.

The champions of this year’s unbelievably exciting Giro — and the public who has followed them — deserve to have their victories and legacies unbesmirched in one of the most memorable Grand Tours of all time.