After the Penguins qualified for the Stanley Cup Playoffs for a 13th straight season, the longest active streak in the NHL, they were swept in four games by the New York Islanders in the Eastern Conference First Round. Pittsburgh was eliminated when the Islanders won 3-1 in Game 4 at PPG Paints Arena on Tuesday.

In all, the Penguins have lost six straight playoff games dating to last season, when they lost Games 5 and 6 of the 2018 Eastern Conference Second Round to the Washington Capitals.

Here are 5 reasons the Penguins were eliminated:

1. Crosby went silent

Sidney Crosby led the Penguins with 100 points (35 goals, 65 assists) during the regular season but was limited to one point, a first-period assist in Game 4, by the Islanders. Throughout the series, Pittsburgh's captain and first-line center said he felt he and his teammates had generated some good chances but hadn't capitalized.

That was true Tuesday, when Crosby hit the left post with Islanders goalie Robin Lehner looking the other way at 9:20 of the second period. A goal there would have tied the game 2-2. Instead, the Penguins were held to one goal for a third straight game.

"We knew what to expect," Crosby said. "They were going to try to force us into making mistakes and capitalize. We knew they were comfortable playing low-scoring games. ... You look at tonight, some of those chances are usually automatic for us. Open nets, hit posts. That's the kind of game that allows them to hang around."

2. Nobody picked up slack

Crosby wasn't the only one struggling, Linemate Jake Guentzel scored one goal after having 40 during the regular season. Center Evgeni Malkin went without a point in the final two games, and forward Phil Kessel was held without a point in the final three. Forward Patric Hornqvist didn't have a point. Defenseman Kris Letang, who has 56 points (16 goals, 40 assists) in 65 games during the regular season, had one assist.

"It doesn't mean we don't try and we're not hungry," Malkin said. "A team won 4-0 [in the series]. They're a better team. We need to understand [why] they play better."

Video: Penguins doomed by offensive struggles vs. Islanders

3. Power outage

Pittsburgh's power play was fifth in the NHL during the regular season, converting 24.6 percent of its chances. But in four games against the Islanders, the Penguins were 1-for-11 (9.1 percent), including 0-for-8 in the final three games.

Coach Mike Sullivan made a change for Game 4 in an attempt to jumpstart the top unit; Guentzel replaced Hornqvist, who normally serves as the net-front presence. But it didn't help; the power play was 0-for-3 on Tuesday.

4. Poor decisions

Before Game 4, Sullivan preached the importance of "playing the game the right way."

That came after Letang took the puck into three Islanders in the Penguins zone, leading to a turnover and a goal from Josh Bailey at 4:39 of overtime in Game 1. It also came after Crosby turned the puck over along the far wall in New York's zone; former Penguins forward Tom Kuhnhackl tipped it to Brock Nelson, who scored on a 2-on-1 rush at 14:24 of the first period of Game 3, putting New York ahead to stay.

But Sullivan's words didn't help. Early in Game 4, Letang got caught at the offensive blue line, leading to a 2-on-1 rush that ended with Jordan Eberle beating Matt Murray to tie the score 1-1. Late in the period, a turnover and poor coverage in front of the net led to Nelson's goal that put New York ahead 2-1.

5. No momentum

The Penguins were unable to score consecutive goals at any point in the series. They took a 1-0 lead in each of the final three games but held those leads for a combined 4:51. In Games 3 and 4, Pittsburgh trailed 2-1 entering the third period. Games 1 (2-2) and 2 (1-1) were tied entering the third period. The series wasn't as lopsided as a sweep might suggest, but the Penguins were never able to generate momentum after they scored.

"It seemed like that was the case the whole series," Sullivan said. "Every time we scored, we get some momentum and we give it back shortly thereafter. It's such a game of momentum."