The Bruins allowed three third-period goals in Friday's season opener, an 8-3 rout by the Florida Panthers.
"We had energy at the start of the first period and the start of the second period," new Boston coach Dave Lewis said. "Somewhere along the way, we lost our mojo. ... We're not going to throw away a month's preparation for the start of the season after one game."
Marco Sturm, Glen Murray and Wayne Primeau scored a goal each in the loss and free-agent signing Zdeno Chara had two assists in his Bruin debut.
Boston (0-1-0) goaltender Tim Thomas stopped only 27 of 34 shots before being replaced by Hannu Toivonen in the third period.
"It's certainly not the opening game of the season I expected or wanted," said Thomas, who has lost nine of his last 10 games, dating back to March 26, with a 3.86 goals-against average over that span.
He was chased in the third period of his only meeting with Tampa Bay on Feb. 11, when he allowed six goals on 34 shots in a 6-5 defeat.
The Bruins dropped their first two games last season before winning three in a row, including a 4-2 win over the Lightning at the St. Pete Times Forum on Oct. 10, 2005.
Boston won both road games at Tampa Bay in 2005-06 and finished 3-1 overall in the season series.
The Lightning (1-0-0) will try to win the first two games of the season for the first time since winning six consecutive games to start their Stanley Cup-winning 2003-04 season.
Ryan Craig matched his career high with two goals to rally the Lightning from a 2-0 deficit to force overtime on Thursday against Atlanta. Vincent Lecavalier then scored the lone shootout goal to give Tampa Bay a 3-2 victory.
"It's nice to get the two goals, but the two points are better," Craig said.
The 24-year-old center had 15 goals and 28 points in 48 games for Tampa Bay last season - his first in the NHL - after being called up from the minors in December.
He also scored two goals on March 17 in a 6-3 win over Philadelphia.
The Lightning outshot the Thrashers 26-11 on Thursday, as goaltender Marc Denis made nine saves and made three more in the tiebreaker.
"He made some big saves," Lecavalier said. "The three guys they had in the shootout are really good."
Tampa Bay signed Denis to a three-year contract in the offseason, after he spent five seasons with Columbus. He posted 93 wins, a 2.97 GAA and a .905 save percentage in 289 games for the Blue Jackets.
The Lightning hopes Denis can improve on those numbers with a better team.
Vaclav Prospal led the Lightning in scoring against the Bruins last season, netting two goals with three assists in four games.
His 10 goals and 26 points in 31 games rank him second all-time for Tampa against Boston, two points shy of Lecavalier, who has 13 goals and 15 assists in 28 meetings with the Bruins.