Nic Dowd and Marcus Johansson scored, and Lindgren made 36 saves in his debut for the Capitals (0-2-0).
"We're doing enough not to win. We've got to clean that up just a little bit," Washington coach Peter Laviolette said. "The more you can remove what is wrong with the game, the mistakes you make, the more you can clean it up, the better chance you have at being successful. And to boot, we are not getting the run support to cover something like that. If you make a mistake but you score five goals, you talk about the mistake inside of a win."
The Maple Leafs killed off the final 41 seconds with the Capitals playing 6-on-4 after Mitchell Marner took a high-sticking penalty and Lindgren was pulled for an extra attacker. They also killed off a slashing penalty by Nicolas Aube-Kubel at 16:15.
"Some huge blocks from [TJ] Brodie and [Justin] Holl facing a power play like that, and a guy who can obviously shoot the puck on the other side like [Alex] Ovechkin, and I thought Samsonov stood tall," Matthews said.
The Maple Leafs went ahead 1-0 at 6:40 of the first period when John Tavares tapped in a pass from Morgan Rielly at the side of the net on the power play.
Dowd tied it 1-1 at 9:57, one-timing a pass in the slot from Erik Gustafsson, who was behind the net.
Johansson put the Capitals up 2-1 at 13:52 of the first period when he shot between Samsonov's blocker and chest protector from the right face-off dot.
"After the second goal, a little bit of a wake-up call for me," Samsonov said. "I needed to do [something] a little bit different. [I was] a little bit nervous. It's hard when you get nervous, your reaction is slow, you're moving bad, but after this, I played better and we got unbelievable work [done] today."