In the wake of all the devastating injuries to the Islanders' back end this season, Andrew MacDonald has done pretty much everything you could ask of a 24-year-old defenseman - logging major minutes, blocking shots and mentoring his fellow young blueliners.

In his 100th career game Saturday, MacDonald found another way to chip in, tallying two goals to lift the Islanders to a 5-2 win over the St. Louis Blues at Nassau Coliseum.

It was a rewarding day for a guy whose contributions often go underestimated or unnoticed.

"He's been our leader back there all season. He probably doesn't get the credit he deserves," said his defensive partner, Travis Hamonic. "It's nice to see him get rewarded like that."

John Tavares, who finished with a goal and an assist, described him as a "heart-and- soul type of guy."

"He doesn't always make the highlights for goals like he did today, but he blocks a ton of shots, takes a ton of hits. He's great at escaping pressure and moving the puck up to his forwards," Tavares said. "He's a tremendous talent and a huge leader in the locker room. He really stabilizes us back there."

With the Islanders up 2-0 in the second period, MacDonald scored on a slap shot from the blue line at 12:49 from the exact spot he scored one game earlier.

MacDonald netted his second goal - and fourth of the season - in the third period, roofing one past Blues goaltender Ben Bishop on a breakaway at 6:22.

"I think that was honestly my first breakaway in my life," he joked.

MacDonald was two inches away from scoring his first career hat trick later in the third, but he hit the post.

"I'm pretty happy with two goals," MacDonald said. "Obviously, the hat trick would've been nice, but two goals is more than plenty."

MacDonald's pair led another offensive outburst for the Islanders, who have nine goals in the past two games. The Islanders have scored at least four goals in eight of the past 15 games.

Tavares got the Islanders on the board at 9:12 of the first with a terrific move to burn two Blues skaters. He matched last season's goal total of 24 with five weeks to play.

"He's not the Number One overall pick for no reason," MacDonald said after describing the move.

PA Parenteau and Michael Grabner also scored to snap significant droughts. Parenteau halted a 10-game skid and Grabner tallied his first goal in nine games.

Grabner picked up an assist on Parenteau's goal, waiting out a Blues defenseman on a two-on-two before sliding it over to Parenteau for an easy one. Earlier in the first, Parenteau missed an open-net goal.

"There's no excuse for missing empty-netters," Parenteau said. "The next couple of shifts, I was thinking, 'What was I doing?' "

After goals by Andy McDonald and Chris Stewart cut the Islanders' lead to 4-2, Grabner went top shelf on a breakaway to provide the final margin. He leads NHL rookies with 26 goals.

"I liked the way we played," Islanders coach Jack Capuano said. "They battled and I thought our young guys played well."

More Islanders