WASHINGTON -- The San Jose Sharks have dominated the Washington Capitals throughout their histories, and entered Tuesday having won 21 of 31 games, including 16 of 17 dating to the 1999-00 season.
"There's no special ingredient," Marleau said. "I think it's just one of those things that it's been going our way for a while. They are always tight games, so it could easily go both ways."
Tyler Kennedy scored in regulation for San Jose (29-12-6), which started a three-game Eastern Conference road trip.
Alex Ovechkin scored and Philipp Grubauer stopped 28 shots for Washington (22-16-8), which has lost five consecutive overtime games.
"It's nice to start the trip off the right way," Sharks coach Todd McLellan said. "It was kind of a back-and-forth affair. They had some momentum [early], but we gained it back. It was a close game between two pretty good teams that played pretty well."
San Jose entered as the NHL's best first-period team with a League-high 51 goals and a League-low 22 against, but Washington got off to a strong start, registering seven of the first eight shots.
The Sharks responded, putting nine unanswered shots on Grubauer, the last of which gave them a 1-0 lead.
The Capitals, who went more than 10 minutes without a shot, failed to clear the zone after a turnover, and the puck came right to Jason Demers. He wristed the puck in the direction of Kennedy as he streaked through the high slot, and his deflection floated up and over Grubauer's reach at 13:30 for his fourth goal of the season.
"It was a good tip," Grubauer said. "I didn't see the pass over and I didn't see Kennedy. It was a tough game. They screened me pretty good, so I had to battle lots of times to find the puck and see around the guy."
The Capitals started the second period by sufficiently testing Niemi again, and they were rewarded at 12:44 when Ovechkin scored on an impressive one-timer, his first shot of the game. Karl Alzner set up the pass, and a sliding Ovechkin ripped a zero-angle shot from near the bottom of the left faceoff circle over Niemi's right shoulder. It was Ovechkin's NHL-leading 33rd goal of the season.
"I shoot the puck and it goes in," Ovechkin said. "One of those shots, it was lucky and a good shot. [Alzner] did a good assist and gave me the puck at the right time and the right spot."
Capitals coach Adam Oates said, "I was actually mad. I was yelling at [Alzner] for not shooting at the time. [Assistant coach Calle Johansson] gave me a hard time. 'How can he pass that shot up? Oh, nice goal.' That was a fantastic shot. That's [Alex]."
The Sharks charged back, but Grubauer stymied them to keep the score 1-1.
As the period came to a close, Brad Stuart thought he restored San Jose's lead, but video review confirmed time had expired before the puck crossed the goal line.
The third period began with the Sharks on an early power play, but a spirited penalty kill by the Capitals never allowed anything to materialize. Washington responded by hemming San Jose in its zone with a few dominant shifts.
With time running out in regulation, Mikhail Grabovski drew the Capitals' first power play when Marleau tripped him en route to the net with 1:15 remaining. Once the Sharks killed off the remainder of the penalty in overtime, the pace quickened considerably as the teams traded chances, most notably Eric Fehr's partial breakaway that Niemi stopped 13 seconds after Fehr hit the outside of the post on the rush.
"[Niemi] was really good," McLellan said. "The power play at the end, he had to make some big saves to give us a chance to get into overtime and he did that."
The Capitals and Sharks, ranked first and tied for second in shootout appearances prior to the game, combined for one goal. Marleau scored in the bottom of the second round, and Niemi turned away Fehr, Ovechkin and Nicklas Backstrom.
"It's huge because we've been struggling a little bit on the road," Niemi said. "It's a really big win for us."
The Sharks continue their trip Thursday against the Florida Panthers.
The Capitals held on to second place in the Metropolitan Division but begin a stretch of eight of nine games on the road against the Pittsburgh Penguins on Wednesday.