TORONTO -- After taking a three-goal lead with an efficient second-period power play, the Ottawa Senators had to rely on a shootout Saturday to defeat the Toronto Maple Leafs 5-4.

"It was early season hockey," Senators coach Dave Cameron said. "We took a 3-0 lead and our power play was working, then they scored two goals."

Then Senators also failed to hold a 4-3 third-period lead and it was left to center Mike Hoffman to score the decisive goal in a 2-1 shootout. It was his first career shootout goal.

"I haven't been too good in the shootouts," Hoffman said. "The ice is really choppy so it's almost tough to deke that late. I had (a plan) set in my mind before I even hopped on the ice."

Center Kyle Turris, left winger Milan Michalek and right wingers Alex Chiasson and Mark Stone scored for Ottawa (2-0-0).

Defenseman Erik Karlsson added three assists for the Senators.

Right winger Joffrey Lupul and centers Tyler Bozak, Peter Holland and Daniel Winnik scored for Toronto (0-2-1).

Defenseman Dion Phaneuf added two assists for the Maple Leafs.

"I thought we did a lot of really good things to fight back in that game," Phaneuf said. "And then they score a 4-3 goal, there's one of two ways to go about that. You can both sit back and pout or you can go back out there and I thought we responded great."

"We were expecting them to make a push." Hoffman said. "We knew that was going to happen. We matched it pretty good and tried to get a bounce-back as quickly as we could."

Ottawa goaltender Craig Anderson made 37 saves.

Toronto goaltender James Reimer made 29 saves.

"What I liked is that we've had a tendency to, when things go bad, to feel bad and we seem to be fragile and we don't just keep playing," Maple Leafs coach Mike Babcock said. "Tonight I thought we kept playing. I would have loved to win the game ... but from where we were, I think it's positive."

Ottawa scored three straight power-play goals in the second period, but Toronto cut the lead to 3-2 before the period ended.

Toronto tied it on a power-play goal at 3:18 of the third on Holland's backhand off a feed from the right point by right winger Pierre-Alexandre Parenteau. It came 10 seconds into a clipping penalty to Senators defenseman Marc Methot.

The Senators regained the lead at 8:59 of the third when Stone deflected a shot by Hoffman.

Winnik tied the game at 16:12 of the third after the Senators gave up the puck in their own end. The goal was waved off at first but a review confirmed that Winnik's shot entered the goal.

Toronto right winger Brad Boyes failed to convert on a breakaway in overtime.

The Maple Leafs went on the power play during overtime when Senators center Mika Zibanejad took a tripping penalty but could not end the game.

The first penalty of the game came at 19:00 of the first when Boyes picked up a hooking minor.

The penalty carried over into the second period and the Senators took advantage when Turris fired home his third goal of the season from the slot on the power play at 0:46.

The Senators scored on the power play again at 3:38 after Leafs defenseman Jake Gardiner was penalized for hooking. Chiassson came out of the penalty box when he finished his elbowing penalty, took a stretch pass from Zibanejad, broke in alone and tucked in a backhand.

The Senators scored their third power-play goal in as many tries when Michalek connected at 4:56 off Karlsson's rebound with Parenteau off for an illegal hit to the head.

Lupul scored for the Maple Leafs at 7:05, taking advantage of an Ottawa turnover.

Phaneuf made a long pass that put Bozak in the clear and he beat Anderson to cut the lead to 3-2 at 14:33.

"Great start, 3-0 lead and it happened to us last year, it happened to us in Buffalo (Thursday), it happened to us tonight," Turris said. "We just find a way to kind of lose our intensity, lose our forecheck and back off a bit. We've just got to find a way to fix it. We squeaked out a win last game, we squeaked out a win tonight. It's something we've got to all learn and find a way to fix."

NOTES: Senators C Kyle Turris, who scored twice in a 3-1 victory at Buffalo on Thursday, wore his Texas Rangers hat at Rogers Centre for the Texas-Toronto Blue Jays American League Division Series game Friday. The hat came from Rangers LHP Derek Holland, a friend from Turris' days in Phoenix with the Coyotes. Turris said he heard some comments, "but everyone was pretty respectful." The Senators changed their practice time to allow the team to attend the game, won 6-4 in 14 innings by Texas. ... The Maple Leafs lost 4-0 to the Red Wings Friday as Toronto's Mike Babcock returned to Detroit, where he coached 10 years and won the 2008 Stanley Cup. ... The Leafs play their next four games on the road, beginning Friday at Columbus against the Blue Jackets. ... After opening the season with two road games, the Senators play their home opener Sunday against the Montreal Canadiens.