The Northeast Division rivals meet for the final time this season Saturday night with first place on the line.
Beaten by the Pittsburgh Penguins in the Jarome Iginla sweepstakes, Bruins general manager Peter Chiarelli acquired Jagr from the Stars prior to the trade deadline.
The 41-year-old netted his 680th goal in odd fashion -- inadvertently deflecting Brad Marchand's centering pass off his skate -- and Tuukka Rask made 40 saves in a 1-0 win over New Jersey on Thursday.
"They always say you've got to drive to the net. Now I know why," Jagr said. "If I'd known when I was 20, I'd have 100 more goals now."
While Jagr is known more for scoring goals as a result of his skills versus his grit, Bruins coach Claude Julien thinks the veteran's tally portends good things because it shows the kind of work needed to score at this time of the season.
"He played his game and his goal was something that we like to see and it's called net drive," Julien told the Bruins' official website. "It doesn't have to be a highlight goal, but he was heading to the net and he wasn't going to get pushed to the side, and it went off his skate and in."
Julien teamed Jagr and Marchand with Tyler Seguin, who is filling in at center with leading scorer Patrice Bergeron sidelined indefinitely due to a concussion suffered in Tuesday's win over Ottawa.
Boston (24-8-4) has won three straight after dropping five of seven and is one point behind Montreal for the division lead.
The Canadiens (24-8-5) have won three in a row at home and four of five overall after beating Winnipeg 4-1 on Thursday. Ryder had two goals and an assist, giving him 17 points in as many games since he was acquired from Dallas on Feb. 26.
"I was used to the city and I knew a few guys here," said Ryder, who played with Montreal for four seasons before joining the Bruins for three as a free agent in 2008. "It was my first time getting traded, so that was the biggest part of it all."
All nine of Ryder's goals with Montreal have come in the last 11 games, including two in a 6-5 shootout victory at Boston on March 27 when the Canadiens rallied from a 5-3 deficit in the final 8:10 of regulation. Tomas Plekanec, who had three assists in that game, is questionable for this one after missing Thursday's contest with a groin injury.
Boston may feel Bergeron's absence since he had two goals and five assists in the last two games between the teams. Seguin, though has posted multipoint efforts in all three meetings this season, totaling three goals and four assists.
Peter Budaj, who stopped all six shootout attempts after relieving Carey Price to start the third period March 27, likely will get a chance to extend his personal winning streak to a career-high seven games. Budaj has a 1.49 goals-against average and .942 save percentage during his run, which includes a 4-3 victory at Boston on March 3.
The Bruins opened the season series with a 2-1 victory at Montreal on Feb. 6 as Seguin and David Krejci each had a goal and an assist.