After the Senators rallied with two third-period goals, Ryan's shootout tally capped a dramatic 3-2 victory over the host St. Louis Blues that snapped St. Louis' two-game skid.
"I think we came in after the second and really weren't down," Ryan said. "I thought physically and emotionally we were still invested in the game. Got the ugly one to start rolling. After losing the way we did (Monday) night, this was a big one."
The Senators, who got third-period goals from Erik Condra and Alex Chiasson to tie it, had lost two in a row, three of four and six of eight. They were beaten 3-2 by the Blues at home on Saturday and then fell 4-3 in Detroit on Monday.
"Thought it was a very hard fought, well-played game," Ottawa coach Paul McLean said. "We battled through 1-0, 2-0, disallowed goals, some adversity to win in a shootout to a very good team.
"It's a big win for our group and a real momentum builder on this road trip. We found a way to win a game on the road in a tough building in a tough situation."
Robin Lehner stopped 27 shots, including all seven he faced in the third period and all four in overtime. He thwarted all three Blues' attempts in the shootout.
"This was a good win for our team," Lehner said. "It was very important for our team to come back here and get two points. We played the right way, tried to get back to a structured game. It's something we needed."
The Blues, who lost No. 1 goalie Brian Elliott to a lower-body injury late in the second period, had won two straight and five of seven.
"Tonight is really disappointing," St. Louis coach Ken Hitchcock said. "The loss is one thing, but the way we played at times is disappointing, attention to detail and focus. Coming back, we took a day off to get re-energized.
"I thought our focus was really inconsistent, poor at times. Execution, not even close to the way we played on the road."
Hitchcock didn't know how long Elliott will be sidelined. Elliott, who earned the win against his former team on Saturday, stopped all 16 shots he faced on Tuesday before being replaced by Allen, who made 15 saves.
The Blues entered leading the NHL in goals-against average, with 2.0 goals allowed per game.
"The goalies have been the heart and soul of our team and the biggest reason why we've been winning," Blues forward Alexander Steen said, "so it's tough to see a guy like Moose (Elliott) go down."
The Blues took the lead with 5:37 left in the first period on a long knuckling shot from defenceman Ian Cole that deflected off Senators defenceman Erik Karlsson and got past Lehner. It was Cole's first goal of the season.
Steen scored during a 4-on-3 power-play with 7:55 remaining in the second period.
Elliott left the game with 6:02 left in the second period after his right leg bent backward during a scramble in the crease. The puck went in the net, but the goal was waved off after a review.
Condra scored his first of the season with 12:05 remaining in the third when he beat Allen on a redirected shot from the point from Eric Gryba to make it 2-1.
The Senators tied it with 40 seconds left in regulation with a rebound goal from Chiasson, his sixth of the season.
Ryan had the best scoring chance in overtime when he beat Allen with a wrister, but hit the right post with 2:54 left.
He found his mark in the shootout with a low wrist shot to the glove side.
"I truly just tried to feather that in," Ryan said. "I used to shoot a lot on the same move and the same area and I didn't get as much on it as I would have liked, but maybe that was a benefit."
NOTES: Blues D Jay Bouwmeester missed his second consecutive game with a lower-body injury. He had played in 737 consecutive games. . D Barret Jackman played in his 745th game for the Blues, passing Brett Hull for third on the franchise list. He trails only Bernie Federko (927) and Brian Sutter (779). . Ottawa LW Milan Michalek and C Mika Zibanejad were healthy scratches for Ottawa. Each had played in all of the Senators' first 20 games this season.