The Giro's 'queen stage', ridden in cold and wet weather, took the riders over the fearsome Passo di Mortirolo, on which Bahrain-Merida's Vincenzo Nobali attacked to split the race apart.
While Sivakov couldn't match the pace of the GC contenders, he rode the climb at his own tempo, in the company of teammates Eddie Dunbar, Ivan Sosa and Sebastian Henao. He then gave it everything on the descent and on the final 15km drag up to the line in Ponte di Legno, finishing the stage in 16th place, just over two minutes behind the group containing Nibali and race leader Richard Carapaz (Movistar).
An aggressive Miguel Angel Lopez (Astana), who started the day just seven seconds behind Sivakov, finished just behind the Nibali group to take 1:41 on the Team Ineos rider, who now sits second in the young rider competition, 1:34 behind the Colombian.
"It was a hard and long mountain stage," explained Team Ineos sports director Nicolas Portal. "The Mortirolo is a tough climb and super steep – it's not a climb that particularly suits Pavel. But I think he managed pretty well. He knew that he could be on his own over the top, but he had support from Sebas [Henao] and Ivan [Sosa]. On the downhill he did a time trial, basically.
"He was pushing hard to hold the gap and I think he exploded a bit in the last three kilometres," continued Portal. "He did a really solid race, and he was happy with the pacing he'd done over the climb. The guys did a great job until the bottom of the Mortirolo, and then we had three guys with him on the climb."
Sivakov goes into Wednesday's stage 17 still in ninth place overall, 7:51 down on Carapaz, and 1:05 behind eighth-placed Simon Yates (Mitchelton-Scott).