This was the second of back-to-back games between the teams. Buffalo earned a 2-1 shootout victory on Tuesday.
Anderson was solid in the third with the Senators holding a 2-1 lead. He made a big early save on Mark Pysyk, and another on Drew Stafford late to preserve the lead. He was called upon yet again in the final two minutes after Milan Michalek took a holding penalty.
"I think Anderson played well," Ennis said. "Scoring goals is hard."
These teams have a history of playing a less-than-exciting games against each other, which could be a reason for the second smallest crowd of the season with just 15,578 on hand.
"We've struggled to put wins together, so when you get four games and points in all of them it's pretty huge," Smith said. "It's good to get going and get the confidence up."
The second period was a struggle for both teams. Ottawa continued to have trouble in its end, but was fortunate as the Buffalo offense had its own problems.
Smith's second-period goal at the 6:39 held up as the winner.
Kyle Turris sent a pass to Smith that bounced off a skate and onto his stick before he swept it past Miller.
Ottawa nearly gave up the first goal but caught a break when John Scott was called for goaltender interference early in the game.
The Senators made the most of the opportunity and scored first as Ryan scored his 15th of the season midway through the period. Turris made a cross-ice pass to Ryan, who was left alone in front.
Buffalo coach Ted Nolan admitted both goals were just a matter of players breaking down for a couple of seconds.
"If you don't turn for one split second, it's in the net," he said. "That's what happened."
The Sabres made it 1-1 on a power-play wraparound goal by Ennis late in the first.
The Senators will look to extend their point streak Saturday afternoon when they take on the Los Angeles Kings.