BOSTON — Bobby Ryan scored on a tip-in on a power play 5:43 into overtime, and the Ottawa Senators recovered after giving up a three-goal lead to beat the Boston Bruins 4-3 Monday night to take a 2-1 lead in the first-round series.

Ryan got free in the zone, tapping it in on assists by Kyle Turris and Erik Karlsson. Mike Hoffman added two goals for Ottawa, with Derick Brassard scoring the other. Craig Anderson finished with 17 saves.

It was the second straight overtime game of the series, and second consecutive win for the Senators following their 4-3 victory in Game 2.

This time Bruins rallied from a 3-0 deficit with three goals in second period, tying the game on a power play goal by David Pastrnak.

Noel Acciari and David Backes also scored for the Bruins. Tuukka Rask stopped 28 shots.

Game 4 is Wednesday night in Boston.

Ottawa seemed to be cruising in the second period following Hoffman’s second goal of the night off a power play to make it 3-0.

But then Boston finally got going on the offensive end.

First, Acciari, who returned from injury, got Boston on the board on a tip-in off a miss by John-Michael Liles. That was followed 42 seconds later by Backes’ slap shot after he broke through the Senators defense to swipe the puck and open the ice.

Then, the Bruins finally cashed in on Pastrnak’s goal with Dion Phaeneuf in the penalty box for slashing.

It nearly nullified what was a dominating start by the Senators, who kept the action on their side of the red line for most of the first period.

The Bruins played through a rash of injuries in the first two games, and were missing defensemen Adam McQuaid, Torey Krug, Brandon Carlo and Colin Miller on Monday.

Acciari and center David Krejci both returned, but Boston struggled early to find much offensive traction.

Hoffman and Brassard scored just 25 seconds apart in the first period and exploited a depleted Boston defense to give Ottawa an early 2-0 lead.

The Bruins made up for their sloppy start and came out more aggressive on the offensive end in the second period, scoring three goals on just seven shots – including the two in 42 seconds – to get back into the game.

The Senators outshot the Bruins 10-3 in the first, taking advantage of several defensive breakdowns on their side of the ice.

It was the first game of the series that the Bruins had trailed after the opening 20 minutes.