Kläbo took his fifth straight championship gold in the sprint.
This after two in the Olympics and two in the WC.
He drilled hard at the front and left the others behind long before the finish line.
Halfvarsson tried to hang on but didn't have the strength.
It otherwise looked very good until the final.
- He didn't have a chance there.
He could not have been in a better position with Erik Valnes gone and no Russians in place, says SVT Sports expert Mathias Fredriksson about Halfvarsson's performance.
It was a Norwegian double victory with Pål Golberg as second.
The Frenchman Jules Chappaz.
Halfvarsson was the fifth qualifier, won the second quarter-final and was a safe runner-up after Kläbo in the first semi-final.
He smiled relaxed before the final, where he left the grid in fifth.
Halfvarsson already impressed during yesterday's training and had "diamonds in his legs", according to Viaplay's expert Johan Olsson, who followed the skaters at the stadium.