No one stepped up more than Hartnell, who has 25 goals, including a league-best 13 on the power play. Coming on the heels of a two-goal performance in Saturday's 4-1 win in New Jersey, Hartnell had consecutive multi-goal games for the first time in his career.
He had four power-play goals over the weekend - two in each game - and his father, Bill, watched him score a hat trick in person for the first time.
Bill Hartnell, a retired teacher and principal, was in town with other Flyers fathers. They will travel with their sons for Tuesday's game in Florida.
"To see the smile on his face afterward is special for me, obviously," Scott Hartnell said after scoring the 13th natural hat trick in Flyers history.
The Flyers, who dropped a 6-0 decision to visiting Boston last month, overcame a 3-1 deficit as Hartnell outscored the Bruins, 3-0, in the second period.
"After a poor start, I think we played our game perfectly," said Hartnell, an all-star snub. "We got pucks, we were physical. I'm not sure how much [Boston defenseman Zdeno] Chara got hit, but that was our main focus - to hit him, get bodies on him, go at him with speed and hopefully he'll turn it over."
Flyers rookies Brayden Schenn and Tom Sestito, each of whom was in a first-period fight, had six hits apiece. The Flyers had their second-highest hit total of the season: 39. Boston had 24 hits.
"We didn't back down from them even though we were missing some key pieces," said Schenn, who delivered a highlight-film hit on Steven Kampfer. Schenn needed stitches to repair a cut on his forehead from his fight with Chris Kelly.
It was a productive weekend for the injury plagued Flyers.
"If somebody tells me before these two games we get three points, I take it, because it's two serious teams," goalie Ilya Bryzgalov said.
Boston connected on both of its shootout attempts, including what proved to be the game-winner by Tyler Seguin.
In the shootout, Matt Read and Wayne Simmonds failed to score, sandwiched around a pretty goal by Giroux.
Opponents have had five shootout shots against Bryzgalov this season - and scored on all five. The Flyers are 0-3 in shootouts this season and an NHL-worst 19-37 in history.
"The goalie has to stop the puck," Bryzgalov said when asked about the Flyers' shootout struggles.
Trailing by 4-3, Boston tied it on David Krejci's tip-in 1 minute, 19 seconds into the third period, then took a 5-4 lead as Daniel Paille's wraparound went off the Bruins' Gregory Campbell and got past Bryzgalov as defenseman Erik Gustafsson failed to clear the front of the net with 15:01 left.
Max Talbot tied it by scoring his second goal of the game - the first was inadvertently deflected into the net by Boston defenseman Dennis Seidenberg, a former Flyer - as he tipped in Matt Carle's point drive on the power play with 9:22 remaining in regulation.
Though not happy to collect just a point, coach Peter Laviolette liked his team's energy.
"Our guys showed up and competed," he said. "We did a couple of things wrong that ended up working against us, but overall the effort was some of the best I've seen all year."
Contact staff writer Sam Carchidi at firstname.lastname@example.org, or @BroadStBull on Twitter.