Finland will face defending champions Canada in the final, who beat United States 4-3, as Russia and the US face off for bronze.

Russia have now failed to win all three of the Men's World Championships they have hosted since independence as the wait for a first home triumph since a Soviet Union success in 1986 continues.

Finland, who have been in ominously good unbeaten form after a victory over Canada in the preliminary phase, were initially outplayed as the home side were roared on by a partisan 12,000-strong crowd.

Sergei Shirokov duly gave Russia the lead in the first period, scoring on his own rebound after a pass from Dmitry Telegin.

But the Finns, inspired by 18-year-old rising star Sebastian Aho, came roaring back with three second period goals.

Aho, a major National Hockey League (NHL) draft prospect, scored twice as Jussi Jokinen added the other Finnish goal.

It brought back painful Russian memories of the quarter-final dual between the same teams at Sochi 2014.

On that occasion Russia also took the lead before the Finns roared back to win 3-1.

The Finns are now guaranteed their first medal since taking silver in 2014, where they lost the final to Russia.

They are one win away from achieving the unprecedented feat of capturing World Junior, under-18, and World Championship gold in the same year.

Canada are on course for a successful defence of their title but did it the hard way, blowing a 2-0 lead before running out 4-3 winners over the US.

The US scored three times in the second period to take a 3-2 lead before Derick Brassard's power-play goal tied up the game going into the third.

Ryan Ellis then scored the semi-final-winning goal with a slapshot to the top-right corner early in the third.

They are one win away from becoming the first team to retain the title since Russia in 2009.