Niemi stopped 34 shots for his first shutout of the season as the Sharks beat the Blackhawks 1-0, winning for the fourth straight time and sending Chicago to its third loss in a row.
Sharks defenseman Jason Demers broke a scoreless tie late in the second period with his first goal of the season, on the power play. That was enough for Niemi, who outdueled Blackhawks goalie Corey Crawford.
The Blackhawks came into the game with 71 goals, second in the NHL, but they couldn't beat Niemi, who won his fifth straight game.
"Unbelievable," Sharks captain Joe Thornton said of Niemi's performance. "That's the reason we got the two points tonight. He played great. For whatever reason, he just likes playing against his old team. Thank goodness for that."
After getting Sunday night off when the Sharks beat Colorado 4-1, Niemi was back in net to face the team he led to the 2010 Stanley Cup. He entered the game 3-1-0 with a 2.84 goals-against average in the regular season against the Blackhawks, who cut ties with Niemi in a salary cap move shortly after winning the Cup. The Sharks swooped in and signed him as a free agent.
After shutting out Chicago for the first time, Niemi acknowledged that facing the Blackhawks was, indeed, not just another game.
"For sure, a little bit (special)," he said, "but I think as time goes by it's less and less."
Niemi, who notched his 14th career shutout and seventh with the Sharks, stopped a flurry of shots on a Blackhawks' power play late in the third period, preserving the Sharks' one-goal lead.
"We really believe he's starting to resemble the Nemo from the past year and really starting to settle in," Sharks coach Todd McLellan said. "He made some tremendous saves, not a lot of rebounds. Just exuded confidence, and our guys were able to survive a night where we didn't play very well."
The Blackhawks entered the game with 27 points to 25 for the Sharks, but the teams were headed in opposite directions. Chicago was coming off a 9-2 loss at Edmonton on Saturday, one day after a 5-2 loss at Calgary. San Jose had won three straight, 5-2 over Detroit at home and back-to-back 4-1 road wins against Dallas and Colorado.
After their loss to Edmonton, the Blackhawks headed to Las Vegas for their scheduled two-day mini-break during their six-game, 13-day "Circus Trip." The Blackhawks got back to work Tuesday in San Jose, and when they took the ice Wednesday night they were intent on making the Sharks work for everything they got.
"We were better around our net," Blackhawks coach Joel Quenneville said. "We didn't give up scoring chances off the rush or the inside play, and I thought we defended down in our zone.
"Every game is different. We had some tough losses, but this is one where we're trending in the right direction."
The Sharks were outshot 23-11 in the first two periods, but they took a 1-0 lead at 18:52 of the second with Demers' goal.
Logan Couture and Ryane Clowe each had a well-deserved assist. Couture won a faceoff against Jonathan Toews in the left circle and a diving Clowe sent the puck toward Demers, lurking all alone above the circle. Demers ripped a slap shot through traffic that deflected off Toews before skipping over Crawford's stick and into the net -- the only one of San Jose's 21 shots to beat the Chicago goaltender.
"It was kind of like a 50-50 puck," said Demers, who has seven points in eight career games against Chicago. "Logan won it back a little bit then Clowe made a great play battling against (Patrick) Sharp. He got it back to me and it was rolling, but you always want to shoot a rolling puck because you never know where it's going and neither does the goalie. I got a good bounce off it."
Demers started the first five games this season, but he struggled and has played in just five of the past 14 games since then.
"For sure, it's a monkey off my back," Demers said of scoring his first goal.
"There's no hiding it. It's been a tough start to the year, but I'm working on things I need to work on. It's paying off slowly. It's one game at a time and one step at a time. I'm happy we got the win and happy I could help out the team any way I could."
The Blackhawks outshot San Jose 13-6 in the second period but couldn't get anything past Niemi. Chicago's Duncan Keith and Viktor Stalberg each launched three shots during the second.
The Sharks nearly broke through earlier in the period when Jamie McGinn fired a shot from the left circle that clanked high off the left post.
The Blackhawks outshot the Sharks 10-5 in the first period and had two power plays to none for San Jose but left the ice with a scoreless tie, thanks in large part to Niemi, who made a handful of brilliant saves. After what happened to Chicago in its previous two games, Niemi said he expected to see plenty of pucks early.
"We were talking about that, their last game," Niemi said. "We knew that for sure that in the first period they were going to come hard."
Niemi got a break early in the period after Sharks defenseman Brent Burns had a horrible giveaway deep in his zone. Chicago winger Marian Hossa came up with the puck with nothing but open ice between him and Niemi. He ripped a backhand from eight feet out, but it sailed well over the net at 7:09.
Later in the period, Blackhawks left wing Bryan Bickell launched a point-blank shot after defenseman Dan Boyle lost and edge and hit the ice, but Niemi rejected it.
Patrick Kane had four of the Blackhawks first-period shots but couldn't beat Niemi.
"That's the standard for how we want to work, how we want to play for each other for 60 minutes," Toews said. "We are not happy with the result, but we are not going to let it hurt our confidence."
The Sharks, who came into the game averaging 34.4 shots per game, had trouble navigating the puck through Chicago's defense to get a shot throughout the opening period.
"We want a couple points from this game, but if we lose games like this we can take those," Blackhawks defenseman Niklas Hjalmarsson said. "Nothing like how we lost in Edmonton and Calgary."
Before their two-day slide last week, the Blackhawks had won four straight games by a combined score of 21-8.
Blackhawks defenseman Brent Seabrook missed his fourth with a leg injury he suffered Nov. 13 against Edmonton. Defenseman Sean O'Donnell was in the lineup for the second straight game, paired with Nick Leddy.