Canada open campaign with win
Canada began their gold medal defence with a tightly fought 3-1 victory over Norway in Group B.
Shea Weber and Jamie Benn put the defending champions two-up heading into the third period, but the Norwegians struck back within 22 seconds of the last session through Patrick Thoresen (powerplay).
Drew Doughty restored the two-score cushion one minute and 25 seconds later, and despite a late surge by the Norwegians, Canada held on for an opening round victory.
"We knew exactly what to expect. We knew they're a tough team, they play physical, they weren't intimidated, they didn't back down. It was a great game from both teams," Doughty said.
Canadian coach Mike Babcock said: "In the first period we didn't execute as good as we'd like to.
"We tried hard. Whether it was nerves, or just that Norway played so hard... if you look at the whole game, they competed like crazy, they made it hard on us."
Hosts Russia suffered a scare in their opening game as they took their Group A match 5-2 against Olympic debutants Slovenia.
Alexander Ovechkin and Yevgeni Malkin scored early for the Russians in the first period but Slovenia fought back at the start of the second session, claiming their first Olympic goal through Ziga Jeglic.
Ilya Kovalchuk took advantage of a Russian powerplay at the end of the second period to add a third for the hosts but they were pegged back again by Jeglic 64 seconds later.
Valeri Nichushkin and Anton Belov added scores for Russia in the final period to put the game beyond Slovenia.
Ovechkin said: "I'm sure everybody was a little bit nervous. It was a crazy crowd and unbelievable atmosphere out there. When you play at home it always makes you a little bit tight.
"The first game is always hard but we played against a good team, a hard-working team, and it was a good lesson for us."
Colorado Avalanche forward Paul Stastny scored twice as USA opened their Group A campaign with a 7-1 win over Slovakia.
Stastny, the son of Slovak legend and Hockey Hall of Famer Peter, helped ensure a routine start for the Americans, who are bidding for their first Olympic gold in 34 years since the "Miracle on Ice" in Lake Placid.
After Tomas Tatar had cancelled out John Carlson's first-period tally, the USA hit six unanswered second-period markers through Ryan Kesler, Stastny (2), David Backes, Phil Kessel and Dustin Brown, with the fifth goal seeing the end of Slovakia netminder Jaroslav Halak.
Carlson said: "That was a pretty cool way to start the Olympics. That first goal made us all feel more relaxed. We felt better as the game went on.
"During the first period we were a little nervous and it took us a while to get focused on what we needed to do."
Finland, bronze medalists four years ago, also overcame an early fright to run out 8-4 winners over Austria in Group B.
Michael Grabner, who helped himself to a hat-trick, and Thomas Hundertpfund twice put Austria ahead in the first period but Mikael Granlund and Jarkko Immonen scored twice as the Finns responded with 14 players among the points.
Finland captain Teemu Selanne, playing in his sixth Winter Games, sustained an upper-body injury in the first period but the 43-year-old Anaheim Ducks forward should be back against Norway tomorrow.
In the women's section, Russia topped Group B with a 3-1 win over Sweden in the Shayba Arena.
Goals from Anna Shukina and Alyona Khomich gave the hosts a two-goal lead before Pernilla Winberg pulled one back for Sweden at the end of the second period.
Yekaterina Smolentseva wrapped up the points for Russia, with just one minute and 53 seconds left.
Shukina said: "The result gave us a psychological lift because we know Sweden is a team capable of winning any medal. That makes it a big achievement for us."
The hosts will now face off against Switzerland in the quarter-finals, while Sweden will play neighbours Finland.
Goaltender Viona Harrer registered a 30-shot shut-out to lead Germany to a 4-0 win over Japan in their final Group B clash.
Franzisca Busch scored twice, including an empty-net marker with 32 seconds left, while Manuela Anwander (powerplay) and Kerstin Spielberger were also on target as Germany claimed their first win of the Games.