Seguin and Peverley, who were traded to Dallas in July in a deal that sent Loui Eriksson to Boston, both scored in the shootout to help the Stars to a 3-2 win at TD Garden on Thursday night.
Lehtonen and counterpart Tuukka Rask each made 34 saves in regulation and overtime.
The Dallas-Boston trade was one of the biggest in the offseason, as the Bruins parted with two players who were integral parts of one team that won the Stanley Cup in 2011 and another that went to the Stanley Cup Final in June. Time and again, the Garden crowd reminded Seguin, who the Bruins selected with the No. 2 pick in the 2010 NHL Draft, that he was no longer in black and gold by booing him whenever he touched the puck and serenading him with a chant of "Se-guin, Se-guin" throughout the latter stages of the game.
"Obviously, it's a great game to win. It will be nice to move on a little bit," he said. "This has been in my head a little bit. You try and put it away when you are playing other games, but it's still there. You are still thinking about coming here to this town. Like I said, the win felt great."
Rask thought he knew the tendencies of his former teammates before the shootout. In the end, even his puck-stopping skills weren't enough to overcome the dramatics he knows often happen when players go against their former teams for the first time.
"Shocking, yeah," Rask said sarcastically. "You always face them in practice; it's a different scenario than that. You think you know what they're going to do, and then they do something else. So you know they were going to score at some point. That's how it always goes when you play against your old team, and they found a way to score a goal."
Seguin said he just wanted to try something different on his former teammate.
"If you want me to be very honest, anyone who asks me, I said I honestly don't know what to tell you. Tuukka is too good of a goalie. I could say the same thing about our goalie; I wouldn't know where to shoot on him. In my head it was kind of do something that you have never done before. I have never really gone right and then gone left on Tuukka before and shot high-blocker. I just tried to read what was open."
The Stars improved to 7-6-2 on the season and 2-0-0 through the first two games of their three-game road trip. They'll conclude the trip against the Detroit Red Wings on Thursday.
"I think we're getting better," Peverley said. "We've definitely come a long way since the start of the year. To come into this building and be able to get two points, I think that's a big confidence booster for our team. I think we've got to keep going and get better."
The Bruins have now lost two in a row and four of their last five. They're 8-6-0 on the season. They hadn't lost to Dallas at home since Jan. 14, 2006. Boston's five-game homestand continues with the second game Thursday against the Florida Panthers.
Bruins coach Claude Julien was frustrated by his team's inability to put the Stars away without reaching a shootout, particularly when they held a 15-1 edge in shots on net during the latter stages of the first period. The coach also pointed to the bad line change that led to Vernon Fiddler's game-tying penalty-shot goal with 2:34 remaining in regulation as another example of his club's recent sloppy play.
Fiddler got behind Boston defenseman Dennis Seidenberg, who had just jumped on the ice, and drew a hooking penalty. Fiddler then roofed a backhander over Rask to tie the game at 2-2.
"Well, it came down to a shootout because we played at the level of the other team," Julien said. "And not to take anything away from them, but I'd like to think we're a better team than what we showed tonight. The first 10 minutes were good, and then we got back to some our old habits. Eventually, when you play that way, you find ways to lose hockey games. And that's what we're doing right now; we're finding ways to lose.
Milan Lucic had given Boston a 2-1 lead at 11:39 of the third period with a tip-in after a strong shift by his line, with center David Krejci and right wing Jarome Iginla, and the defense pair of Dougie Hamilton and Seidenberg. Iginla won a battle in front that allowed Krejci to retrieve a rebound and dish the puck back to Hamilton at the blue line. The defenseman's wrister was timed perfect for a Lucic tip through an Iginla screen.
It took the Stars 3:38 to put their first shot on goal, but they made the most of it. After Zdeno Chara knocked down Jordie Benn's chip-in, Jamie Benn picked up the puck along the right wall, skated to just inside the right dot and beat Rask with a wrist shot inside the far post for an early 1-0 Dallas lead. The Benn goal extended the Bruins' streak of allowing the first goal to four games.
The Bruins wasted little time before answering. Torey Krug forced his former teammate Peverley to turn over the puck along the right wall of the Dallas zone. Carl Soderberg passed the puck across the ice to Smith, who fed it back to a streaking Krug for a goal from the left side of the slot at 4:16.
The Bruins finished the period with an 18-10 advantage in shots on goal, and the teams went to the dressing room tied 1-1. The Stars carried over their late-period momentum into the second period. They took over the lead in shots on net by outshooting Boston 13-4 over the middle 20 minutes. Rask made all the saves, as did Lehtonen, who had to be good to keep the puck out of the net on back-to-back Boston power plays in the middle part of the period.
"I thought the guys responded well," Stars coach Lindy Ruff said. "We took the early penalty and that gave them a little bit of momentum. They had us back on our heels. Once we got midway through the period, we started to come around. At the start of the second, our guys did a tremendous job. I thought Benn and Tyler started the period with an unbelievable shift, and I thought that turned the game."