"They have a lot of good young players over there," Tkachuk said. "They are a young team with nothing to lose."
Tkachuk scored his first two goals with Atlanta to help the Thrashers to their fourth straight win, 4-2 over the Panthers on Tuesday night.
Ilya Kovalchuk and Marian Hossa continued leading Atlanta's dominance of Florida. The Thrashers are 6-0 against their Southeast Division rival this season and have won 10 straight over the Panthers at home.
"Atlanta has an All-Star lineup and taking [a lot] of penalties against those guys is not going to work in our favor," Florida's Chris Gratton said after his team tied a season high with 10 infractions. "I don't think it was the refs' fault."
Scoring his 35th goal with two assists, Kovalchuk has 11 points in the season series. His wrister made it 3-2 with 6:24 remaining. Tkachuk's second goal, on a power play, capped the scoring with 1:51 remaining.
"When we acquired Keith, we knew he is a great player and a veteran, but he has an unbelievable presence at the net," Atlanta coach Bob Hartley said. "He is strong, smart and knows how to position himself."
Hossa has six goals and eight points against Florida this season.
"We didn't play much even-strength," Panthers captain Olli Jokinen said. "Both teams were fouling hard. Some fouls weren't called. The first 20 games, they called everything. Then they go back to the old rules. That's tough."
Tkachuk, acquired in a Feb. 25 trade with St. Louis, opened the scoring on a breakaway when he skated past Bryan Allen and beat Belfour to the glove side with a backhander 2:41 into the game.
"We had a lot of chances," Tkachuk said. "We had a couple of five-on-threes, and you should be able to take advantage of those."
Stephen Weiss' 17th goal, coming on the power play, pulled the Panthers to a 1-1 tie at 1:04 of the third.
Atlanta began the night holding sixth place in the Eastern Conference and tied with Tampa Bay, which visits Vancouver, for the Southeast Division lead.
The Panthers had won a season-best four straight and were 6-2-2 in their last 10.
"When the game was on the line, they scored on the breakaway, and we didn't," Florida coach Jacques Martin said of Kovalchuk's goal. "We had a chance in the second period, but we didn't score."
Lehtonen stopped 38 shots to improve to 29-19-8. In 13 career games against Florida, Lehtonen is 11-1.
"Kari made some unbelievable saves and bailed us out in the second period," Hartley said. "He is playing like a veteran now and he is confident in there."
Belfour dropped to 20-14-8 after stopping 25 shots.
Craig Anderson, making his season debut as a reserve goalie, replaced Belfour for a combined 44 seconds at the end of the second and at the outset of the third. He faced one shot as Belfour left the ice for an undisclosed reason. ... Atlanta is 15-5-6 against the Southeast. ... Florida is 8-12-3 against division rivals. ... After losing five straight at home and nine of 11 overall, the Thrashers have a three-game winning streak in Atlanta.