The 22-year-old smashed the record set by Switzerland's Dario Cologna in 2009 by an impressive 223 days by clinching top spot in Italy.
The young Norwegian dominated from the off after completing the 15km course in 40:52.6 during Saturday's mass start and he never looked back by seeing off the challenge of silver medallist Sergey Ustiugov by 16.7 seconds in the 9km pursuit climb 24 hours later to take top spot.
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Speaking after the race, Klæbo said: "It was really tough, I was really tired after yesterday and I heard all the way from the bottom that Sergey [Ustiugov] was quite fast.
"I was just trying to push myself, but it's quite cool that I won.

Klaebo wins yet again in Val Di Fiemme

"I saw him all the time, so it was really tough to see him coming closer and closer mentally, but it was really good to be on top."
Norwegian Simen Krueger claimed bronze – finishing 48.8 seconds behind the overall victor.
The result in Val di Fiemme ensures Klæbo maintains his stranglehold on the overall standings and leads second-placed Russian Alexander Bolshunov by 124 points.
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