Now, Tampa Bay, led by dynamic scorer Nikita Kucherov, will face New York and captain John Tavares for the right to go to the conference final.
Despite the fact that the Lightning fell two victories short of winning the Stanley Cup last spring and were second in the Atlantic Division in 2015-16, there is little that separates them from the Islanders, who were the first wild card.
New York, from the Metropolitan Division, had three more points than Tampa Bay and knocked off Atlantic champion Florida, winning each of the final two games in the second overtime.
These teams have met one other time in the postseason, and it worked out very well for Tampa Bay. In 2004, the Lightning defeated the Islanders in five games in the first round and used that victory as the springboard for a march all the way to the only Stanley Cup championship in their history.
Lightning: The line of Alex Killorn, Tyler Johnson and Kucherov dominated in the first round against the Detroit Red Wings, scoring 10 of Tampa Bay's 12 goals. Kucherov had five goals, and his eight points led the Lightning. Killorn had three goals, including the game-winner in Games 1 and 5, and Johnson tied a Lightning record with four points in Game 2 and had seven points (two goals, five assists) in the series.
Video: TBL@DET, Gm4: Kucherov scores a pair in Detroit
Tampa Bay is still looking for secondary scoring to complement the top line and hopes the line of Ondrej Palat, Valtteri Filppula and Jonathan Drouin can capitalize on its scoring chances more in the second round. Drouin had four assists in the first round; three came in Game 4, including one on Palat's game-winning goal. He had 13 shots in the series.
Captain Steven Stamkos is unlikely to return during the series. He has been out since having surgery April 4 to treat a blood clot near his right collarbone. J.T. Brown is sidelined with an upper-body injury.
Islanders: The Islanders offense was predictably carried by Tavares, who had five goals and four assists in six games against the Panthers. Tavares came on strong at the end of the regular season, and it carried into the first round. He scored the tying goal with less than a minute left in Game 6, then scored the winner in the second OT.
Right wing Kyle Okposo, who can become an unrestricted free agent July 1, had a goal and five assists in six games. Okposo spent the first round skating alongside Tavares, so the opportunity for continued production should be there.
Video: NYI@CAR: Okposo's spinning shot beats Lack
Alan Quine didn't make his NHL debut until the final weekend of the regular season, but he's made the most of his promotion from Bridgeport of the American Hockey League. Quine scored the game-winner in the second overtime of Game 5 and saw time on the top line with Tavares and Okposo during the final two games against Florida.
Frans Nielsen, who had three goals in the first round, started the series on Tavares' left wing but was shifted back to center when the Panthers got center Vincent Trocheck back from injury in Game 5. It will be interesting to see where Nielsen plays against the Lightning, who are expected to be without Stamkos.
The Islanders' fourth line of Matt Martin, Casey Cizikas and Cal Clutterbuck struggled at times against the Panthers but will get a fresh start against the Lightning. They'll be used to play a physical style and will be given the responsibility of trying to wear down Tampa Bay's forwards.
Lightning: Tampa Bay gave up eight goals in five games against the Detroit, and the defense held up well without Anton Stralman, who has been sidelined with a broken leg since March 25.
Victor Hedman played 30:02 in Game 4 and averaged a Lightning-high 27:01 in the series. He's unquestionably the leader on the blue line and will continue to play big minutes in the second round.
Matt Carle has found success while paired with Hedman, suggesting they could remain together even if Stralman is able to play at some point in the second round.
In Game 5 against the Red Wings, the Lightning defense struggled with giveaways, forcing goalie Ben Bishop to make several difficult saves.
"We played pretty well defensively most of the series," coach Jon Cooper said. "We held them to eight goals in a five-game series and only one power-play goal. If you can do that, you're giving yourself a really good chance to win. For the most part, I thought we played well for four of those games and the goalie had to bail us out in one."
Islanders: Nick Leddy led the way for New York in the first round; he had three assists in six games and played nearly 80 minutes combined during the final two games of the series. Leddy's skating ability is his greatest asset, as shown on Tavares' tying goal in Game 6.
Leddy is paired with Travis Hamonic, who healed enough from a lower-body injury in time for Game 1 against Florida. Hamonic is solid at each end of the ice. He played more than 39 minutes in the double-overtime win Sunday.
Calvin de Haan has tremendous hockey sense and continues to show a willingness to sacrifice himself in order to make a play; de Haan blocked 18 shots in the first round. He is also capable of making a solid first pass out of the defensive zone or skating the puck up ice, if need be.
Johnny Boychuk struggled at the start of the series against Florida but improved as it progressed. His leadership and experience (Boychuk won the Stanley Cup with the Boston Bruins in 2011) will be huge.
Thomas Hickey continues to be responsible at each end of the ice; he scored in overtime in Game 3 and consistently makes the smart play in his own zone. He'll likely be paired by Marek Zidlicky at the start of the series, but there's a chance rookie Ryan Pulock could return before its conclusion. Pulock had a goal and two assists in the series before his upper-body injury in Game 4.
Lightning: Bishop made 34 saves, including three on breakaways, to help Tampa Bay close out its first-round series against Detroit with a 1-0 Game 5 victory. It was the fourth Stanley Cup Playoff shutout of his career and the third to end a series.
Video: DET@TBL, Gm5: Bishop shuts out Red Wings in clincher
It was the type of performance the Lightning have come to expect from Bishop, who had a 1.61 goals-against average and .950 save percentage in the series. He didn't allow a goal in the first period in any of the five games and only gave up one in the third.
"You always want your goalie to keep you in it. I think [Game 5] was an instance where he might have won us the game," Killorn said. "It's such a confidence-booster when you have a guy like that back there."
Islanders: There were questions whether Thomas Greiss could be the No. 1 goaltender in the playoffs, but he dismissed those against the Panthers.
Video: NYI@FLA: Greiss makes two great stops in double OT
Greiss was brilliant in the first round, which featured one of the best performances in recent memory when he made 47 saves in a 2-1 double-overtime win in Game 5. Greiss had a 1.79 goals-against average and .944 save percentage in the series.
Jean-Francois Berube, claimed off waivers from the Los Angeles Kings prior to the start of the season, will back up Greiss while Jaroslav Halak continues to heal from a lower-body injury.
Lightning: Cooper had to shuffle his lineup without Stamkos and Stralman, and then made a few more changes when Brown became unavailable to him because of an upper-body injury sustained in Game 2. His confidence in Carle and Drouin was rewarded.
If Stralman returns during the second round, Cooper will have some decisions to make. Will he stick with the Hedman-Carle defense pair? Will he dress seven defensemen and keep Nikita Nesterov in the lineup if Brown doesn't return?
Assistant Rick Bowness coaches the penalty-kill unit that held Detroit to one power-play goal on 25 chances.
Islanders: Capuano found a way to guide New York to its first playoff series victory in 23 years. Now he'd like to keep it going.
Capuano wasn't afraid to take chances or mix lines during the first round, and the Lightning should be ready for his on-the-fly adjustments in this series.
Capuano's main task will be to find a way for the Islanders to be better at 5-on-5. They had a lot of trouble against the Panthers at even strength despite winning the series.
Lightning: The Tampa Bay penalty kill was the best in the League during the first round of the playoffs (96.0 percent). Cooper gave a lot of the credit to Filppula, who did the job of winning draws, allowing the unit to clear the zone. The Lightning also blocked 82 shots in the five-game series, many of them on the penalty kill, with forwards Brian Boyle and Ryan Callahan leading the way.
Cooper would like to see more production out of the power play in the second round. The Lightning had three power-play goals in Game 5 but were 4-for-23 in the series.
Islanders: The power play performed well in spurts during the regular season but got it together at the right time. New York was 23.8 percent (5-for-21) with the man-advantage in the first round, highlighted by Quine's double-overtime goal in Game 5. If the players show a willingness to shoot rather than look for the fancy play, it should lead to more success against Tampa Bay.
If he's able to return, Pulock could provide the Islanders power play with a boost; the rookie defenseman has a slap shot that is regularly clocked at more than 100 mph.
Just as it did during the regular season, the penalty kill got the job done in the first round (13-for-15), thanks in part to Greiss. Nielsen, Cizikas, Clutterbuck and Nikolay Kulemin will continue to be relied upon against some pretty talented Lightning forwards.
Lightning: Victor Hedman, defenseman -- As well as Tampa Bay played on defense in the first round, it will have to be better going against Tavares, Okposo and the rest of New York's talented group of forwards. The Islanders will try to use their speed and take advantage of any open space on the ice to pressure the Lightning defense and get good shots on net. Hedman will be relied upon to play more than 25 minutes per game and keep Tavares off the score sheet. He will also be asked to do more offensively and help get the power play going.
Islanders: Kyle Okposo, forward -- New York benefited from five goals by Tavares in the first round and will need him to do something similar against the defending conference champions. Okposo scored once on 28 shots in the first round; one has to think his fortunes will change if he continues to get chances.
WILL WIN IF...
Lightning: Kucherov can continue his dynamic play from the first round and Tampa Bay can get scoring from Drouin and Palat on the second line. Each team likes to play fast, and there is a good possibility of high-scoring games. The Lightning will have to continue to take advantage of their opportunities to try to rattle the confidence of Greiss early in the series.
Islanders: New York can't be afraid of its opponent, a team that came within two wins of the Stanley Cup last spring. Now that the Islanders know the grind necessary in order to win a series, they must continue to be resilient and get at least a similar performance, if not better, from Greiss in order to have a chance. They'll also need to get more secondary scoring.