Ineos Grenadiers' Italian rider Ganna had set a time of 52:01 and looked set to win the stage when Pogacar found himself behind after the second intermediate checkpoint, but the Slovenian made up time on the brutal climb to the finish line.

Pogacar crossed the line at 51:44, punching the air as he went 17 seconds faster than a resigned-looking Ganna to extend his overall lead and retain the Maglia Rosa.

His second stage victory of his Giro d'Italia debut was a huge statement in the general classification battle in which he extended his advantage from 46 seconds on Thursday to two minutes and 36 seconds heading in to stage eight.

It was a punishing day for Ineos Grenadiers rider Geraint Thomas who slipped down to third in the standings, 10 seconds second-placed behind Dani Martinez (Bora-Hansgrohe).

Pogacar once again looked in a class of his own as he blew away his rivals as he has done all season.

"I started a bit with an easier pace and had to get used to the TT bike and then I paced myself until the climb and then went full gas so I'm super happy with today," the UAE Team Emirates rider said.

"I knew the climb suited me and that was my advantage especially as it was quite steep."

Thomas said he "lacked it a bit" as he could only finish in 10th place -- behind teammates Ganna, American Magnus Sheffield who was third and fourth-placed Thymen Arensman.

Martinez finished eighth on the day and he and the other GC contenders will have to try and bounce back on Saturday in the 152km stage from Spoleto to Prati di Tivo -- a tough route featuring 3,850 metres of climbing.