Malkin, the NHL's leading scorer, banged a long carom off the end boards past Washington's Michal Neuvirth for his 26th goal of the season. Malkin added two assists to give him a league-leading 58 points on the season.
James Neal scored twice and assisted on the game-winner for Pittsburgh, which has won six straight. Kris Letang scored for the second straight game Marc-Andre Fleury stopped 17 shots for the Penguins, who beat Washington at home in the regular season for the first time in more than four years.
Alex Ovechkin matched Malkin, a fellow Russian, with a goal and two assists. Alexander Semin had a goal and an assist for the Capitals while Brooks Laich added a goal.
The Capitals kept the league's hottest team under wraps most of the game, overcoming an early two-goal deficit to take a 3-2 lead 1:08 into the third period on Ovechkin's 20th goal of the season, a one-timer off a perfect feed from Semin.
Neal drew Pittsburgh even with his second goal of the game, beating Neuvirth with a wrister from the right slot to tie it 3-3. The Capitals nearly extended their unbeaten streak at Consol Energy Center to nine games late in the third, but Troy Brouwer's slapshot from the right circle clanged off the far post in the final minute of regulation.
It was all the reprieve the Penguins would need.
Pittsburgh controlled the brief overtime. Neal fired a long shot from the point that sailed wide of the net but caromed off the boards and onto the stick of Malkin on the right post. He had little trouble getting it by Neuvirth as the Penguins beat their rivals at home in the regular season for the first time since Dec. 27, 2007.
Neuvirth overcame a shaky start to finish with 23 saves but couldn't stop the Capitals from losing for the third time in four games. Washington is now 8-12-3 since Dale Hunter took over for Bruce Boudreau in November.
One of those victories was a 1-0 win over Pittsburgh on Jan. 11, a game that changed the Penguins' season.
Though the defeat extended Pittsburgh's losing streak to six games — the franchise's worst stretch in two seasons — Pittsburgh coach Dan Bylsma thought he saw a flicker of improvement in his team's execution and attitude.
He was right. Pittsburgh hasn't lost since, the team's longest winning streak since ripping off 12 straight wins from Nov. 17-Dec. 11, 2010. That team, however, was at full strength. These Penguins are still missing captain Sidney Crosby, who remains sidelined indefinitely with concussion-like symptoms.
At the moment, Pittsburgh is getting by just fine without their superstar.
Having Malkin in top form has certainly helped. Fully healed from the torn ACL in his right knee that cut short his 2010-11 season, Malkin has been arguably the best player in the game over the last two months and has lately shown a flair for the dramatic.
He posted a natural hat trick in the third period of a victory over Tampa Bay last weekend and scored the game-tying goal late in regulation before collecting the shootout winner in a 5-4 victory over Montreal on Friday night.
Pittsburgh didn't look like it would need Malkin to save the day after racing to a quick 2-0 lead. Letang beat Neuvirth on a long slapshot from the point on the power play to put the Penguins on the board 4:51 into the game and Neal doubled Pittsburgh's advantage just over a minute later.
The Capitals responded with three straight goals during a 10-minute stretch spanning the second and third periods, capped by Ovechkin's blast.
Yet it wasn't enough — for once — as Malkin kept Pittsburgh's hot streak going. He has 17 goals and 17 assists — the most in the league — since Crosby went out of the lineup when concussion-like symptoms returned following a Dec. 5 loss to Boston.
NOTES: The Capitals scratched defencemen Tomas Kundratek and Jeff Schultz and centre Marcus Johansson. ... Pittsburgh scratched defenceman Ben Lovejoy and forward Arron Asham, who is out indefinitely with a concussion. Asham is the sixth Pittsburgh player this year to be diagnosed with concussion-like symptoms. ... The Capitals host Boston on Tuesday while Pittsburgh travels to St. Louis.