Alex Ovechkin, right, celebrates his second-period goal with center Nicklas Backstrom. Backstrom has been in a scoring slump recently. (Jonathan Newton/Washington Post)

Early in the regular season, it became clear the Washington Capitals would need to go through the upstart Tampa Bay Lightning to win the Southeast Division. After four months of jockeying, Washington triumphed for a fourth consecutive Southeast crown.

With the teams’ Eastern Conference semifinal series slated to begin with Game 1 Friday at Verizon Center, the Capitals find themselves with the familiar Lightning serving as a roadblock once more.

Washington went 4-1-1 against Tampa Bay in the regular season, but that statistic may be a misnomer. The Capitals posted a 2-1-1 record in the final four meetings, each of which featured flared tempers and accusations of unsportsmanlike play.

“It got pretty good there at the end, I think, the rivalry,” Coach Bruce Boudreau said. “Just because both teams were vying for first place, and I think the last four games we had against them were pretty serious, serious games. But I think this takes it a different step.”

To advance, Washington will need to have its star players outshine Tampa Bay’s, secure more constant special-teams efforts, maintain discipline when emotions run high and have its goaltender stand up against potent scoring threats.

The Capitals benefited from their forward depth toknock the New York Rangers out of the first round in five games, getting key contributions from the third and fourth lines. If Alex Ovechkin and Alexander Semin are the only top-six forwards to record more than one goal in this series, though, Washington may struggle to match the Lightning’s offensive capabilities.

The most conspicuous absence on the scoresheet so far this postseason is No. 1 center Nicklas Backstrom. Held to one point against New York, it will be clear soon enough if the 23-year-old Swede’s struggles were purely related to that opponent or the start of a significant drought.

There can be no larger stage for Washington’s all-star roster than on special teams, either. The Capitals received timely power-play goals in the first round (3 for 18) but the Lightning has inflicted maximum damage on the man-advantage this postseason with a 29.6 percent success rate (8 for 27).

Neither Washington’s penalty kill (19 of 20) nor Tampa Bay’s (34 of 35) allowed more than one goal in the first round.

But the continued steadfast reliability of one of those units is likely to change during the series. The Capitals need to ensure it isn’t theirs that suffers a breakdown.

“I think that’s a big challenge, and obviously that’s a big key in the playoff series,” Backstrom said. “We have to make sure we know what they’re gonna do. They have great players on the power play too. We just have to avoid it as much as we can.”

Discipline will play a role in simply not giving the Lightning’s effective power play any opportunities, but it will likely be up to both team’s veterans to play the role of metronome.

While Tampa Bay may be making its first trip to the second round of the playoffs since 2004, when it won the Stanley Cup, there are three players — Martin St. Louis, Vincent Lecavalier and Pavel Kubina — who played integral parts in that championship season.

The Capitals have been galvanized by postseason disappointment, and only Jason Arnott, who has played 16 games with Washington, was a prominent part of a Stanley Cup winning squad.

Then there is what should be a superb battle in goal, where veteran Dwayne Roloson, 41, and rookie Michal Neuvirth, 23, will see far more dangerous offensive threats than they did against Pittsburgh and New York, respectively. In the American Hockey League, Neuvirth developed a reputation as a netminder who relishes games in which the stakes are the highest. Much may hinge on whether he can surpass the grizzled Roloson, who also carries a background of success when it matters most.

Those elements helped Washington wrestle the top spot in the division away from the Lightning during the regular season, and they can aid the effort once more. As this rivalry takes a turn into the playoffs, though, Tampa Bay is determined to not allow Washington through this time.

“The way we look at it, it’s time to change. We want to be the top team,” Lightning forward Sean Bergenheim said. “If you have this team that has been considered for a while to be number one and a new team that’s trying to take their spot, they’re feeling threatened and we really want that spot.”