Logan Brown, Colton Parayko, Brayden Schenn, Kasperi Kapanen, and Tyler Pitlick also scored for the Blues, who had a four-goal second period. Thomas Greiss made 22 saves for his sixth win of the season.
“It’s always nice to come back to San Jose. It’s a good city," said Greiss, who was drafted by the Sharks in 2004 and was with the organization until the 2013-14 season. "The Shark Tank is a very nice place to play, and it’s fun to play here.”
Alexander Barabonov had a goal and assist for San Jose. Logan Couture and Steven Lorentz also scored, and James Reimer made 17 saves in his 16th loss of the season.
The Sharks got off to a hot start just 3:50 into the game. Barabanov tucked his 12th goal of the season after Andreas Johnsson gave him an alley-oop pass. The assist by Johnsson was his first point since joining San Jose.
Couture added to that just 2:41 later after Couture blasted a one-timer over Greiss' glove for his 21st goal.
But the Blues got it going in the second period with three goals in the first 9:30.
“We went from playing a good brand of hockey to completely abandoning what we did in the first period," Sharks coach David Quinn said. "Just very sloppy and individualistic.”
At 2:35, Parayko was left alone in the slot for his fourth goal of the season. Kyrou got his 26th after Buchnevich made a sweet pass from behind the net less than three minutes later to tie it at 2.
Brown scored his first goal of the season at 9:30 after Buchnevich yet again made a nice pass into the slot.
“Yeah, Buchnevich made a great play and just tried to fire it under the bar," Brown said. “(The) goalie was down and out. So it’s definitely relieving and got the monkey off the back.”
The Blues finished off their big second period with a tic-tac-toe play resulting in Schenn's 17th goal of the season that made it 4-2.
“We had a really good first (period) and a pretty solid third, too," Reimer said. "But that second period just got a little out of control. We dipped, and it’s just too bad. It was ours for the taking.”
Lorentz kept the Sharks with a short-handed goal 6:36 into the third period. It was his first career short-handed goal.
Pitlick made it 5-3 with 5:08 remaining in the third after a Sharks turnover. Kapanen capped it with an empty-net goal after Buchnevich found him on a cross-ice pass. It was Kapanen's first goal since the Blues claimed him off waivers.
“(Buchnevich) has been doing that for most of the year,” Blues coach Craig Berube said. “I mean, he’s been a real good player all year long in all situations, and he’s a great passer. He sees the ice really well, and he did some real nice things with the puck.”
San Jose Sharks defenseman Erik Karlsson has played in 900 career NHL games.
The Sharks acquired Vladislav Namestnikov from the Tampa Bay Lightning in exchange for Mikey Eyssimont on Wednesday.
Blues: Visit the Los Angeles Kings on Saturday.
Sharks: Host the Washington Capitals on Saturday.
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