TAMPA, Fla. -- Matthew Tkachuk made his long-awaited return to the lineup and was back to his old self quickly on Tuesday night for the Florida Panthers, who opened this postseason the way they ended last postseason: With a win.

Playing for the first time in more than two months after dealing with a lower-body injury, Tkachuk scored two second-period goals in his return game, as the Panthers handled the rival Tampa Bay Lightning 6-2 in this Eastern Conference first-round series opener at Amalie Arena.

Those two goals were both of the power-play variety, the first putting Florida up 4-1 -- the second goal for the Panthers in a 14-second span -- and the next one pushing the lead to 5-1 midway through the second period.

It was just like old times: Tkachuk got twisted up with Tampa Bay's Brandon Hagel -- someone he fought during the 4 Nations Face-Off tournament -- after one whistle, took the game's first penalty on a roughing call (leading to Tampa Bay's first goal), then made sure his name was all over the score sheet.

Florida coach Paul Maurice, in his in-game, bench interview with ESPN's Emily Kaplan, said he was comfortable with what he was seeing from Tkachuk in his first game back and expected him to "be the difference-maker" for the Panthers.

"That's what he is for us," Maurice said. "He's got an incredible set of hands, got an incredible gift for the emotional needs of a game, when you need a hit, when you need a big play. He's been great for us."

Sam Bennett and Sam Reinhart also scored for the Panthers, and veteran defenseman Nate Schmidt, not known for his offense, added two more goals, as Florida, which won the Stanley Cup last June, hammered an Atlantic Division foe in front of a sellout crowd, setting up an all-important Game 2 on Thursday.

Tampa Bay goaltender Andrei Vasilevskiy will need to be sharper in that game, after a Tuesday performance to forget. The two-time Stanley Cup winner allowed all six goals on just 16 shots, closing with a .625 save percentage. Across the ice, Florida's Sergei Bobrovsky made 20 saves en route to the win.

"The series isn't won in one game, so there's a positive. We had a bunch of guys tonight playing their first playoff games, and I thought guys handled it fairly well," Tampa Bay coach Jon Cooper said. "But in the end, we gave up six goals. We're a pretty decent defensive team, and we have a very good [penalty-kill unit], and we gave up three [goals] on that. ... In the end, those are areas of strength of ours, so I'm pretty confident we can button those up, and we'll be OK."

Jake Guentzel, in his first season with the club, and Brayden Point scored for Tampa Bay. But the Lightning played the final 33:30 without center Anthony Cirelli, and it showed. There was no immediate word why the 27-year-old center was out.

"We gave up 16 shots, and that's usually a good night, but tonight wasn't that. They're a good team, we know they have good players," Tampa Bay defenseman Victor Hedman said. "So, for us, it's all about refocusing, make sure we have a good practice tomorrow, and get ready for the next one."

Whether Tkachuk would even play in Game 1 wasn't certain until just before game time. Tkachuk went through practices Saturday and Monday, then took part in the team's day-of-game skate Tuesday before the decision on his return was made. Maurice even indicated that it could come down to the final few minutes before the 8:48 p.m. start time of the game.

"It's not really a guy you can put a label on," Schmidt said of Tkachuk. "He's such a unicorn of a player. But, more than anything, just how he is in the room, getting the guys fired up for the game, you feel his energy, you feel his excitement."

Tkachuk hadn't played for the Panthers since Feb. 8 because of a lower-body injury suffered during the 4 Nations Face-Off tournament two months ago. He missed the team's final 25 games of the regular season, yet still finished with 22 goals and 57 points -- third most on the team in all three categories. He was also second on the Panthers this season with 11 power-play goals.

"There's no better time to be an athlete," Tkachuk told Kaplan in a postgame interview, in reference to the postseason. "This is the time of our lives. And just getting a win here in Game 1 is the cherry on top."

Panthers forward Brad Marchand, acquired at the NHL trade deadline from the Boston Bruins, made his postseason debut for his new team in the win and also played with Tkachuk for the first time. Marchand had an assist and two shots on net in his 17:15 of ice time, and seemed to fit right in with Florida's dominant forward group.

"Both teams will look at the tape and find things that they can do better," Maurice said after the win. "But there isn't an established identity to the series yet."

The Associated Press contributed to this report.