The teams were tied 3-3 after the first period before Belov scored his first goal at 18:02 of the second. Belov's second goal at 3:57 of the third broke a 4-4 tie and his assist and Roman Lyubimov's goal at 8:38 provided the margin of victory.
Goalie Sergei Bobrovsky (Columbus Blue Jackets) made 15 saves for Russia (1-0-0-1), which outshot Kazakhstan (0-1-0-1) 49-19.
"Giving up four goals is a lot, and it's impossible to be happy with my game after giving up so many," Bobrovsky said. "But the most important thing is that we won, and we can move on to the next game."
Russia plays Latvia (0-0-2-0) on Monday. Kazakhstan plays Norway on Tuesday.
Norway 4, Switzerland 3, OT: Andreas Martenson scored with 1:37 remaining in overtime in a Group A preliminary-round game in Moscow.
Norway (0-1-0-1) rebounded from a 3-0 loss to Denmark on Saturday. The Swiss (0-0-2-0) rallied from a 3-1 deficit with two third-period goals, the second from defenseman Felicien Du Bois with 10 seconds left.
Defenseman Raphael Diaz (New York Rangers) had two assists for Switzerland.
Sweden 5, Denmark 2: Forward Mikael Backlund (Calgary Flames) scored twice, Linus Omark had three assists and Sweden (1-1-0-0) moved into a first-place tie with the Czech Republic (1-1-0-0) in Group A with a victory in Moscow.
Denmark (1-0-0-1) took a 1-0 lead into the second period before Sweden responded with four goals in 12 minutes.
Forward Gustav Nyquist (Detroit Red Wings) also scored and forward Jimmie Ericsson had two assists for Sweden. Nikolaj Ehlers (Winnipeg Jets) and Jesper Jensen scored for Denmark.
Sweden plays the Czezh Republic on Monday. Denmark plays Switzerland on Tuesday.
Slovakia 5, France 1:First period goals by defensemen Andrej Sekera (Oilers) and Dominik Granak gave Slovakia an early lead en route to a win in a Group B preliminary-round game at Yubileiny Arena in St. Petersburg.
France's Jordann Perret scored 1:09 into the game before Slovakia responded with five unanswered goals. Julius Hudacek made 24 saves for Slovakia (2-0-0-0), which plays Germany on Tuesday. France (0-1-0-1) also plays Tuesday against Hungary.