Flyers goalie Antero Niittymaki ranged far out of the crease to poke away a loose puck and prevent a breakaway. But the puck went to Ward near the right boards. Ward easily beat Niittymaki with a slap shot.
"He didn't have a chance to place the puck," Ward said. "He just had a chance to knock it away. He was squeezed with the choice of coming out of the net. That's why I started going up because he had to get rid of it. It was a 50-50 chance of going to my side."
Niittymaki could've gloved the puck and risked a possible delay of game penalty.
"It was the only thing I felt comfortable doing. It didn't work," Niittymaki said.
Marco Sturm, Marc Savard and Peter Schaefer also scored for the Bruins, who snapped a two-game losing skid.
Daniel Briere, Jeff Carter and Scott Hartnell had goals for Philadelphia, which had won three straight to close out a 5-1 road trip.
After being outplayed from the start of the second period, the Flyers scored twice in a span of 2:04 in the third to tie it at 3.
Hartnell slipped one past goalie Alex Auld during a power play midway to cut it to 3-2. Briere scored his 17th goal on a backhander off a rebound of Simon Gagne's shot to tie it with 7:15 left.
Niittymaki made 28 saves, the least effective performance in his fourth straight start. He had allowed five goals in four games since Dec. 30, including a team-record 54 saves in a 3-2 win at Toronto last Saturday.
Niittymaki's recent play fueled talk of a goalie controversy. Flyers coach John Stevens already said Martin Biron would start at Washington on Sunday.
The Bruins went ahead 2-1 when Sturm scored from behind the net after Niittymaki lost sight of Zdeno Chara's slap shot from the point.
Savard's goal during a two-man advantage in the second period tied it at 1. Savard's slap shot from the slot sailed over Niittymaki's shoulder.
"It's huge to win this game," Savard said. "Guys are working hard and Philly is one of the teams that's ahead of us, one of the teams we have to catch. We made the big plays when we had to and we got the two points."
Carter gave the Flyers a 1-0 lead on a power-play goal midway through the first period. Randy Jones fired a shot wide of the net. The puck kicked right back to Carter, who put it in for his 17th goal.
Shortly after Niittymaki made a sprawling save on David Krejci early in the third period, Schaefer gave the Bruins a 3-1 lead by deflecting in Chara's slap shot.
Auld stoned Hartnell on a breakaway to temporarily preserve the two-goal cushion early in the third.
"It's a good feeling to come back and get a point," Briere said. "If we play the way we did in the third period, we're a dangerous team."
Notes: Chara had three assists. ... The Bruins hadn't scored on their previous 10 power-play chances before Savard's goal. ... Flyers F Scottie Upshall returned after missing five games with a sprained right ankle. ... Hartnell has four of his 11 goals in the last two games. ... Bruins F P.J. Axelsson sat out with a foot injury.
