Impey now leads the race by just two seconds after he gained five out on the road, finishing behind Richie Porte's team mate Mads Pedersen at the first intermediate sprint but besting him at the second.
"Fantastic job," Impey said. "Two seconds up, I don't know if it's enough but we've given ourselves every chance to try and win this bike race and it's all up to tomorrow."
But the biggest winner of the day was Nizzolo with NTT Pro Cycling executing their race plan to perfection and claiming their first win since August last season.
With the race fracturing after Porte took the KOM points on Kerby Hill as the Australian and a select group containing Impey, Lucas Hamilton, Simon Yates and Rohan Dennis got away, Nizzolo's team waited and worked hard back with the chasing bunch, making the catch 10kms from the finish.
"I can't thank (my team) enough," he said. "Because today they did a great job. That was the plan. If I was to be dropped they were to wait for me on the climb and they did it perfectly.
"And then as well they did a perfect lead out. I was (in the) perfect place. and then i just put on the pedals everything I had and it worked in the end and so I'm so happy."
Impey said his group not staying away after Kerby Hill was one hitch in an otherwise perfect plan.
"(It went) exactly as we planned on the climb," he said. "Lucas (Hamilton) did a hell of a team (job) there. There was only ten guys left so we had a very select group.
"And I was praying that group would make it to the line because I fancied my chances there. But like i said we gave it everything we could but...really chuffed with today.
While Porte didn't sound concerned at Impey's new advantage, he expressed some frustration at being isolated by his team on today's stage.
"It's not a massive deficit tomorrow. I think we can win the stage and win the race but we're going to have to have guys up there, I was a little isolated today."
Aussie Rob Power (Sunweb) again finds himself just nine seconds in deficit to the race leader.
And Ewan? Here he explains what happened today: