Luongo made 28 of his 52 saves in a frenzied third period to help the Florida Panthers snap San Jose's six-game winning streak with a 3-2 victory on Tuesday night.
''We gave them the two points there,'' Sharks defenseman Jason Demers said. ''That's unacceptable.''
Marty Havlat and Brent Burns scored, but the Sharks were lackadaisical on defense in the second period and came up empty on four power plays in the third period to lose the game.
That cost San Jose a chance to move past Anaheim for first place in the Pacific Division. The teams are tied with 97 points heading into Thursday's showdown at the Shark Tank, but the Ducks have a game in hand.
The Sharks came in with the best home winning percentage in the NHL, but four of their nine losses at home have come against the bottom four teams in the inferior Eastern Conference - Carolina, the Islanders, Florida and Buffalo.
''We've talked about this lesson a lot of times this year already with teams that are maybe not in the playoffs and we keep shooting ourselves in the foot,'' coach Todd McLellan said. ''Until we fix that, we'll probably end up with the same results.''
Brandon Pirri scored one goal and set up Quinton Howden for another in a 17-second span of the second period and Scottie Upshall also scored for the Panthers, who had lost seven of their previous eight road games.
But Luongo was the biggest reason for the win, especially in the third period when Florida was outshot 29-2 had to kill off four power plays, including 51 seconds of a two-man advantage.
San Jose had the extra skater for all but 27 seconds in a span of 7:36 during the middle of the period but couldn't get anything by Luongo.
''I haven't seen a performance like that in a while,'' Howden said. ''That was impressive. It was tough taking those penalties but you have confidence with the guy back there. He was our best penalty killer tonight.''
Burns finally broke through on San Jose's 26th shot of the period when he knocked a puck past Luongo after a faceoff win by Joe Thornton with 3:03 remaining.
But Luongo robbed Joe Pavelski in the final minute to preserve the win.
San Jose has failed to score on 34 of its past 35 power plays at home since Feb. 3, with the only goal coming early in the second period when Havlat beat Luongo with a slap shot from the high slot.
''It's not good enough, simple as that,'' Sharks forward Logan Couture said. ''It's on us, the players who go out there and play the big power play minutes, myself included. It needs to be better, it needs to help win us games.''
The Panthers took over the game after Havlat's goal and led 3-1 heading into the third. Pirri changed the tenor of the game on one shift. It started when he raced past Jason Demers and put a shot on goal that Niemi initially saved. But the puck popped in the air and landed behind Niemi, hit his skate and trickled into the net.
''It's an opportunity here and, when you get those opportunities, you have to make them count,'' Pirri said. ''We created some speed down the wings and maybe they didn't cover the gap as well as they would have liked. I just shot it.''
Just seconds later, Pirri got another shot on goal that trickled through Niemi and was sitting in the crease where Howden knocked it in for his third goal in four games this season.
The Sharks put on heavy pressure in the closing minutes of the period, but Luongo was up to the task and the Panthers added an insurance goal with 14.8 seconds to play when Pavelski lost the puck near the boards and Joey Crabb slid a pass to Upshall, who beat Niemi with a one-timer.
''In the second period, I don't think we used our head,'' Demers said. ''We were working hard, but weren't working smart.''
NOTES: F Jonathan Huberdeau (upper body) did not make the trip for the Panthers. ... Sam Tageson, a teenage hockey player with a life-threatening heart condition, practiced with the Sharks, skated through the shark head before the game and was introduced to a loud ovation before the game as part of a day arranged through the Make-A-Wish Foundation and the Sharks Foundation.