Alex Ovechkin scored his first goal of the season for Washington (1-3-1), and Darcy Kuemper made 13 saves. The Capitals have scored six regulation goals in five games this season.
"I think we had lots of opportunities," said Ovechkin, who had 14 shots on goal. "I think we played the right way but we're just in that period of time when we have to fight through it and don't be panicking, don't be frustrated. It's just part of the process. I think we just have to play hard and [the puck] goes in."
Rielly gave the Maple Leafs a 1-0 lead at 12:53 of the first period with a power-play goal when he took a pass at the bottom of the right circle from Timothy Liljegren and beat Kuemper far side.
Toronto was outshot 17-5 in the first period.
"He kept us in it in that first period," Matthews said of Woll. "They really came out flying and kind of took control of the game pretty early on, and he was just solid for us. He gave us a chance to hang in there."
Ovechkin was awarded a penalty shot at 2:45 of the second period after he was hooked by Mark Giordano on a breakaway, but Woll made a blocker save on his backhand attempt.
"I was just trying as best I can to let myself make the read and not be guessing too much," Woll said.