ATLANTA -- Through 82 games last season, Tampa Bay was two points better than Atlanta in the race for the final playoff spot in the Eastern Conference.
Second-year center Ryan Craig scored Tampa Bay's first two goals, including a game-tying shot about two minutes into the third period.
"It's nice to get the two goals, but the two points are better," Craig said of the win.
Denis, who came to Tampa Bay in a trade with Columbus, struggled in the opening period, allowing two goals on six shots. He was perfect the rest of the way.
"He made some big saves," Lecavalier said. "The three guys they had in the shootout are really good."
"You can't ever get down when you are down a few goals," Denis said of Atlanta's 2-0 lead after the first period. "Goals are going to come in this league. You have to stay after it."
Each team was called for eight penalties, all minors.
"We understand we have a penalty problem," Denis said. "If we can stay out of the box, we'll be OK."
Lecavalier, the first shooter for the Lightning in the shootout, beat Kari Lehtonen with a shot to the right edge of the net.
"I went high," Lecavalier said. "I tried to get him down, and I put it as high as I could."
Added Lecavalier of the 6-foot-4 Lehtonen: "When you look at him, you don't know where to shoot, he's so big."
Brad Richards was stopped by Lehtonen on Tampa Bay's second and final shot of the shootout.
Lehtonen, limited by injuries to only 38 games last season, proved his return to health by stopping 24 shots through overtime.
"I was really disappointed," Mellanby said. "We were prepared. I thought we came out and had them on their heels."
The Thrashers' 11 shots tied the team record for fewest in a game set on Feb. 21, 2002 at St. Louis. It was the lowest shot total at home in club history.
Lehtonen's 2005-06 troubles began when he suffered his first groin injury in the first period of the season opener. He survived the whole game Thursday night.
Atlanta, which led the league with 58 power-play goals last season, was back in business with the advantage early. Mellanby's first goal on a slap shot came only nine seconds after Tampa Bay's Nikita Alexeev drew a minor penalty for hooking.
Mellanby tipped in a pass from Hossa for the goal. The delicate shot was hit with so little force it barely reached the back of the net.
Less than six minutes later, the Thrashers took advantage of a 5-on-3 advantage by patiently making several passes before Hossa took a pass from Mellanby across the front of the net and scored from the right edge for a 2-0 lead with about seven minutes left in the period.
Thrashers coach Bob Hartley said his players "cheated themselves tonight" by blowing the 2-0 lead.
"We had a great camp," Hartley said. "Those guys are in great shape. Why we stopped skating, I'll have to look at the tape and figure out some answers."
Atlanta's early patience developed into too much passing in the second and third periods.
"We were passing a bit too much and began to run around," Mellanby said. "They've got a lot of experience with guys that won a Stanley Cup, and they really smothered us."
The Lightning answered with a power-play goal four minutes into the second period. Craig tipped in Richards' long shot from between the circles.
- Thrashers D Braydon Coburn opened the season on the injured list after hurting his shoulder in a preseason game at St. Louis on Sept. 24.
- The Lightning won last season's series with the Thrashers 4-3-1.
- Atlanta faces Southeast Division opponents in nine of its first 10 games.
- Craig tied for the Tampa Bay lead with eight points in the preseason.
- Thrashers D Steve McCarthy had two assists.