But the Sharks had more pressing concerns for teammate Dan Boyle.
Boyle was lost for the game with a head injury suffered early in the first period.
Boyle was taken off on a stretcher early in the first period following a check from behind by the Blues' Maxim Lapierre, who was ejected from the game for checking from behind.
A Sharks spokesperson said Boyle was alert and responsive on the way to the hospital. Boyle will be kept overnight for observation.
Thornton was one of the first players on the ice.
``He wasn't (saying anything) and that's what was so scary,'' Thornton said. ``I've never seen a guy be like that before. It just takes your breath away. He wasn't responding or anything. It was very, very scary.''
Several Sharks players were critical of Lapierre afterward.
``It's just disgusting to see that type of play in hockey, when a player that probably shouldn't even be in this league is taking out one of the best players in the world,'' said Sharks center Logan Couture, who had a goal and an assist. ``(Lapierre) has got a history.''
Added Joe Pavelski, who scored his first goal of the season: ``Idiots are idiots out there. Dan is a world-class defenseman ... (Lapierre saw) straight numbers (in front of him). There's guys in the league that will target that ... It doesn't matter, they'll just go. It (stinks). Guys responded appropriately.''
Sharks coach Todd McLellan gave the good news of Boyle's status.
``Well, he left and he went to the hospital and from what I understand, he's doing OK,'' McLellan said. ``A very scary moment, needless. It doesn't have to happen in our game. It doesn't have to happen.''
Blues captain David Backes also expressed his concern afterward.
``No one in their right mind would ever want that to happen to another guy,'' Backes said.
``Our thoughts and prayers are with Dan Boyle and his family. That's a scary thing, it's something you hope never happens. Hopefully he has a speedy recovery and he's back on the ice soon.
``Nobody ever wants that to happen. It's a tough thing to see that and to put it behind you and keep playing. That's disturbing.''
The Blues, who dropped to 4-1-0 on the season, had their 10-game regular-season home winning streak snapped as the Sharks won in dominating fashion.
``It's tough because it's Dan Boyle and there's so much respect in this office because of history with Dan,'' Blues coach Ken Hitchcock said.
``I haven't really looked at it that closely on the video to be honest with you, so I don't want to comment on it until I looked at it a few times,'' Hitchcock added. ``I don't think that had anything to do with the outcome today. One team played hard and smart.''
After the Boyle injury, it was a penalty-filled first period, with 79 minutes in penalties handed out.
Lapierre was ejected for a five-minute checking from behind penalty as well as fighting, as was teammate Ryan Reaves.
The Sharks also lost forward and Matt Pelech with a fighting major and game misconduct. Andrew Desjardins was originally awarded a fighting major and 10-minute game misconduct, but was changed to a 10-minute misconduct and he was able to return for the second period.
The Sharks took a 2-0 lead on power-play scores from Couture and Pavelski just 48 seconds apart.
Both goals came from the left circle, with Couture scoring at 9:37.
The Blues trailed on home ice for the first time since April 16, 2013, a stretch of 568:47.
Pavelski one-timed his first of the season on the short side past Halak just after a 27-second two-man advantage for the Sharks expired.
The Sharks added to their lead in the second period, getting goals from Wingels and Hannan to grab a 4-0 lead.
Wingels scored on a wraparound off the skate of Barret Jackman 8:34 into the period for a 3-0 lead, and Hannan with his first of the season off a slap shot with 2:47 left in the period for a 4-0 lead.
Thornton made it 5-0 on a shot from the slot, beating Elliott 5:06 into the third period off a pass from rookie Tomas Hertl.
Tarasenko hammered home a rebound off a shot from Jaden Schwartz at 7:23 of the third period to make it a 5-1 Sharks lead. Polak's shot from the low slot with 7:32 remaining cut the Sharks' lead to 5-2.
Marleau added his fifth of the season at 17:06, the Sharks' third power-play goal of the game and put a stamp on a game they dedicated to their teammate.
``Your heart kind of drops,'' Thornton said. ``It's tough seeing a teammate go down like that. We had to give a good effort for Dan tonight. I've never seen that before, you're just kind of sitting on the bench hoping Dan is OK. It takes a while to kind of get back focused again.''
NOTES: Hertl leads the NHL in rookie scoring with nine points. ... San Jose's win was only its second in the past eight meetings with the Blues. ... The Blues' previous home regulation home loss was April 14, 2013, to Chicago. ... The Sharks lead the NHL in goals (30) and goal differential (plus-21). ... Polak's goal was his first since April 11, 2013, second in two seasons and 10th of his career.