The second-round Eastern Conference playoff series is tied 2-2. Game 5 in the best-of-seven set is Saturday in Washington.
The Capitals took their first road loss after starting the postseason 4-0 away from home.
The Penguins got a scare during the first minute of the second period when, during delayed penalty call against Malkin, goaltender Matt Murray took a shot off what appeared to be his collarbone area.
He crumbled forward and was checked by trainer Chris Stewart but remained in the game.
Pittsburgh broke a scoreless tie at 9:21 of the second period when Guentzel batted a flopping rebound past goaltender Braden Holtby and inside the far post. It was his team-leading ninth goal of the postseason, and he added his 10th later.
Guentzel extended his point streak to eight games.
"(Guentzel is) doing a great job," teammate Sidney Crosby said. "I don't think there's any denying that. He works hard. He does a lot of good things with and without the puck. I think he cares more about the wins more than the goals and assists. So he's been a big part of our team's success."
Guentzel was in the penalty box for tripping the Capitals' Lars Eller when Washington tied it. T.J. Oshie's one-timer from the slot sailed over Murray's glove for a power-play goal at 12:55 of the second period.
Pittsburgh scored a power-play goal at 17:31 of the second for a 2-1 lead, but this one had to withstand a review and a challenge.
There was no call initially, but a review showed that Malkin lunged toward the puck as it sat near the goal line and pushed it just over before Holtby pulled it back out with his glove. A review resulted in a goal call, and a challenge from the Capitals on goaltender interference was not upheld.
Malkin was playing in his second game after returning from a lower-body injury.
"When I stayed on the ice, I thought it was no goal," Malkin said after the game. "I didn't see the puck cross the line. I got so mad because it's a good chance to score, but after, there's a replay and it's in. It gives me a little more confidence, and I'm glad. I had a great chance last game and it hit the post again. This game is crazy, but it's good like that."
Guentzel added an empty-net, power-play goal with 57.4 seconds remaining in regulation.
Washington played without winger Tom Wilson, who served the first game of his three-game suspension for an illegal hit to the head of Penguins rookie winger Zach Aston-Reese in Game 3. Aston-Reese sustained a broken jaw and a concussion.
The Penguins got winger Carl Hagelin back for the first time this series. He wore full-face protection because of a mouth injury,
Murray made 20 saves for the win. Holtby stopped 21 shots.
"We've believed in ourselves all year," Holtby said. "One game at a time. Now this game isn't going to shake us at all. Our biggest asset has been bouncing back, either after a win or a loss. Just focus on playing our game, and that's what we're going to do. I don't think anyone in here believes any different."
--Field Level Media
Washington | Pittsburgh | |
T.J. Oshie 1 | Points | Jake Guentzel 2 |
T.J. Oshie 1 | Goals | Jake Guentzel 2 |
Nicklas Backstrom 1 | Assists | Sidney Crosby 2 |
T.J. Oshie 1 | Power Play Goals | Jake Guentzel 1 |
N/A | Short Handed Goals | N/A |
Braden Holtby .913 | Save Percentage | Matt Murray .952 |
Braden Holtby 21 | Saves | Matt Murray 20 |
Team | Shots | Goals | Power Play | Penalty Kill | Penalty Mins | Face Offs Won |
Washington | 21 | 1 | 1-3 | 2-4 | 13 | 26 |
Pittsburgh | 24 | 3 | 2-4 | 2-3 | 11 | 26 |