Niemi kept the Canucks from doubling their lead with a big stop on Ryan Kesler with 5 minutes to go in the period.
Canucks forward Chris Higgins had a chance off the rush early in the third that Niemi was equal to before the Sharks, who had just 17 shots through two periods, started to come on.
After Sedin missed a wide-open net off a feed from his brother Daniel, Luongo made a big glove save on San Jose forward James Sheppard with under 8 minutes to go.
"We're trying to find ways," Boyle said. "That's what it's all about and in this league with the extra points they are giving now, it's just going to come down to the end of the year and you never know which extra point is going to solidify your playoff position or have you on the outside."
The Canucks returned home after a 1-2-1 road trip against Pacific Division rivals, with the only victory coming against the Sharks 4-2 last Thursday. That win snapped Vancouver's nine-game losing streak against the Sharks dating to last season.
The Sharks swept the Canucks four straight in the first round of last season's playoffs, after Vancouver got the better of San Jose in five games in the 2011 Western Conference finals.
Playing their first home game since a 4-0 victory over the Toronto Maple Leafs on Nov. 2, the Canucks had a couple of early chances in a first period that was short on action.
Niemi stopped defenseman Chris Tanev on a chance in the high slot 5 minutes in before shooting out his left pad to stop Mike Santorelli on the doorstep a few moments later.
Vancouver's No. 1-ranked penalty kill was put to the test midway through the period when defenseman Alexander Edler was whistled for interference. The Sharks moved the puck around to Joe Thornton, but the San Jose captain's heavy shot from the top of the faceoff circle rang off the crossbar behind Luongo and stayed out.
"You're not going to win every game you play great, and sometimes you don't deserve to win and you're going to win," Luongo said. "That's the way the NHL is. I think the main thing is we can't put our heads down."
NOTES: The Canucks' power play entered ranked 28th overall. ... NHL great Gordie Howe was in attendance and got an ovation midway through the second period. ... Vancouver left wing David Booth returned to the lineup after completing a conditioning assignment in the American Hockey League. ... The Sharks play Friday night in Edmonton. ... The Canucks continue their season-high six-game homestand Sunday against Dallas.