Phil Kessel backed James Reimer's 29 saves with 1 win over the Senators on Saturday.
Colin Greening scored in the closing minutes for Ottawa, which got 15 saves from Ben Bishop. The Senators dropped into second place in the Northeast Division earlier Saturday when the Bruins earned a shootout victory over the Flyers and sit seventh in the Eastern Conference.
The Maple Leafs grabbed a 1-0 lead 7:20 into the second courtesy of an Ottawa gaffe. Connolly was credited with his 11th goal of the season when a clearing attempt from behind the net by Senators defenseman Erik Karlsson bounced off of Bishop's skate and into the cage.
Toronto put the game away with a pair of power play tallies in the third.
The first came less than a minute into the final period, when Kessel drifted in front and wristed the puck past a screened Bishop.
With under eight minutes to play, Phaneuf made it 3-0 with a slap shot from the right circle.
Reimer came within 1:09 of his fourth shutout of the season, but Greening's tip-in made it 3-1, sealing the final result.
Boston is in first place in the Northeast Division with 85 points. Ottawa has 84...This was the sixth and final meeting between the teams this season. Each team won three games.