Ryan Callahan scored a power-play goal midway through the third to give Tampa Bay its fifth straight win, 5-4 over Ottawa, and hand the Senators their fifth loss in a row.
Tampa, who sits second in the Atlantic Division with 83 points and 11 games remaining, is peaking at the right time.
"We just seem to be scoring tons of goals," said Lightning goaltender Ben Bishop, who stopped 27 shots for his 34th win of the season. "We're rolling right now and we have a big game against Pittsburgh so hopefully we can keep it going."
The Senators have talked about the need to play better and play smarter, but head coach Paul MacLean says it's the same mistakes that keep coming back to plague his team time and time again.
"Groundhog day," MacLean said. "Thirteen giveaways, six minor penalties, we played too much in our zone and ends up in the same thing."
Teddy Purcell scored twice for the Lightning (39-24-7). Valterri Filpulla and Eric Brewer also scored.
Clarke MacArthur, Erik Karlsson, Ales Hemsky and Milan Michalek scored for the Senators (28-28-13). Robin Lehner faced 28 shots as he lost his sixth straight game.
Trailing 5-4, Ottawa had a great opportunity to tie the game as Callahan took a penalty with 55 seconds remaining in regulation. With Lehner on the bench, the Senators had a two-man advantage, but were unable to beat Bishop.
"We competed to the end, but once again we didn't find a way to win," said Senators captain Jason Spezza. "We fought right to the end, but once again we found a way to lose."
Callahan's power-play goal midway through the third had given the Lightning a 5-3 lead, but the Senators made it a one-goal game as Michalek deflected a Karlsson shot from inside the blue-line at 17:07.
Brewer scored his first goal in 95 games to give the Lightning a 4-3 lead at 3:48 of the third with a great shot off his backhand to sneak the puck in under the crossbar.
"I've seen him do that a few times," said Bishop. "He's good for a couple of those a year."
Hemsky made it 3-3 after displaying some great puck handling before beating Bishop late in the second. The goal earned him a standing ovation from the 17,136 on hand.
"It's a nice goal, but in the end it really doesn't matter if you lose," said Hemsky. "The people reacted great."
Asked if he minded being the goalie on the end of Hemsky's highlight-reel goal, Bishop could only laugh.
"It doesn't really matter when you win," he said. "It doesn't matter how many highlight goals they score if we win the game."
The Lightning had taken a 3-2 lead at the five-minute mark of the second period on a power-play goal by Filpulla, who knocked home a rebound just out of Lehner's reach.
Lehner was at a loss for words after the game.
"What is there to say now, I don't know, it's pretty empty," he said. "It's tough to be in there right now. I can say again, yeah I sucked … I'm trying to be there and trying to step up to make saves, but the players are so good in this league and they get too much time. It's tough.
"I don't think the effort has been the biggest issue this year. I think we're cheating some times. We go really offensively and then it's pretty empty back home."
The Senators ended the first period tied 2-2 after getting off to a horrible start. Purcell, who hadn't scored in his last 19 games, opened the scoring just 23 seconds into the game.
Ottawa managed to tie the game on MacArthur's short-handed goal midway through the period. It was MacArthur's 21st of the season, tying a career high.
The Lightning regained the lead on Purcell's second of the night as he managed to dig the puck out through traffic in the crease and then shoot it in off the post.
Karlsson rounded out the scoring with a power-play goal, beating Bishop with a shot from just inside the blue-line.
Notes: G Craig Anderson (upper body injury) and G Nathan Lawson (lower body injury) missed the game. D Patrick Wiercioch and LW Matt Kassian were a healthy scratch for the Senators … The Lightning signed free agent forward Cody Kunyk to a one year, two-way NHL contract. Kunyk, 23, skated in 37 games for the University of Alaska-Fairbanks Nanooks this season, posting 22 goals and 43 points. D Keith Aulie, D Mark Barberio, C Tom Pyatt and RW Nikita Kucherov were healthy scratches for Tampa.