"That's Johnny," said Monahan, whose six goals lead Calgary. "We see it day in, day out. He's got great hands and he's got quick feet. He reads the game better than anyone I know. If you get open in a quiet area, you're usually going to find the puck. It showed again tonight."
WATCH: All Capitals vs. Flames highlights
Micheal Ferland scored, and Gaudreau had two assists for the Flames (6-6-0), who are 2-4-0 at home, including 1-1-0 to start a season-high seven-game homestand.
"Any win feels good, but especially right now at home, it was the one that we needed the most," Monahan said.
Gaudreau has eight points (two goals, six assists) in his past seven games.
"We have a 2-on-1 at first and I think [Capitals defenseman John Carlson] slid at the right time, but I couldn't get the puck across to [Monahan], so I just pulled up," Gaudreau said of the rush that led to the game-winning goal. "I was looking for a [defenseman] at first and their guys flew into the crease area and didn't catch [Monahan] on the backside there. I just zipped it down to him. I think their guys were screening their goalie a little bit, and we had a nice little tap-in."
Jakub Vrana scored, and Philipp Grubauer made 36 saves for the Capitals (5-6-1), who went 1-2-0 on a three-game, Western Canada road trip. Washington is 2-5-0 in its past seven games after starting the season 3-1-1.