Oshie has four points (one goal, three assists) in two games after missing the previous 11 because of a lower-body injury.
"Just nice to have a guy that's not afraid to make a play and if it's not going to work out, he's not afraid to make another one after that," Capitals center Evgeny Kuznetsov said of Oshie. "You have to have lots of games behind your back to be able to execute and make some plays and not be afraid to make mistakes."
Kuemper made 15 saves in the first, including a pad save on Tyler Toffoli alone in front with 1:56 left.
"We talked about coming out [well] in the first [period] and we did," Flames forward Elias Lindholm said. "After that they took over and were the better team."
Kuznetsov made it 2-0 at 16:37 of the second on the rush when he skated between defensemen Chris Tanev and Nikita Zadorov, cut to his left and slid the puck under Markstrom's right pad as he was falling to the ice.
"It's amazing," Oshie said. "[Kuznetsov] does so many things that they're still impressive, but not surprising anymore. He's such an impactful player for us, such a huge part of our success, so to see him going is great."
Ovechkin extended the lead to 3-0 at 12:24 of the third, scoring on a wrist shot from the left circle after controlling a pass across the slot from Conor Sheary with his skates.
"That's why we play soccer before the games, you know?" Ovechkin said.