Fourteen Islanders were out there on the ice for an optional practice Wednesday, feeling good about themselves after a win over the rival Rangers the night before and a 4-0-1 run over the last five games. After slipping so often over the first 20 games, the Isles have finally been skating in the right direction.

“Things are easier when you’re winning,” defenseman Thomas Hickey said. “You wake up, you’re not as sore the next day. Morale is better. It’s more fun to come to the rink. That helps. That sort of breathes a little bit of new energy into it. That’s been noticeable around here. You can feel it.”

Jack Capuano wasn’t at Northwell Health Ice Center, away for what the Islanders said were “personal reasons.” The coach is due back for Thursday night’s game against St. Louis at Barclays Center.

If he had been around, he could have cited the reasons for the improvement by this 10-10-5 team that experienced a 6-10-4 start. More goals for one. The Isles have scored 15 over the last four games. But the penalty kill and goalie Jaroslav Halak may top that on the resurgence scale.

The PK has killed off all 19 chances over the last seven games and 20 straight overall.

“It just sort of creates predictability when you do it right a few times and you just get on a roll,” Hickey said. “It’s like a well-oiled machine. We’re all in the right positions and efficient with our clears and our faceoffs.”

One of their prime penalty killers sees this efficient stretch being about puck luck, too.

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“I think the puck, as poorly as it bounced for us in the first 15, it bounced exactly the opposite way in the last 10,” Cal Clutterbuck said.

Then there’s Halak.

“There’s a saying in hockey: ‘Your goalie is your best penalty killer,’ ” Hickey said.

Take the first period against the Rangers. Halak made nine saves after Brock Nelson got hit with a double minor. The Rangers finished 0-of-6 on the power play.

“He was amazing . . . especially on that kill in the first period,” Hickey said.

Halak has started the last three, sandwiching a 38-save shutout at Washington and his 36-save work against the Rangers around the 4-3 OT loss to Detroit, which also came with 30 saves.

“He’s been great, not only on the PK, just overall throughout the games,” Nelson said. “He’s kept us in a few games and won us a few.”

Nelson sees the overall improvement like this: “I think maybe just everybody’s on the same page, trying to keep it simple, work hard.”

So bring on the Blues.

“I think we’ve put ourselves in a position where we’ve earned a little bit of confidence here the last little stretch,” Clutterbuck said. “It’s nice to win a couple.”

Notes & quotes: Johnny Boychuk missed the Rangers game with flu-like symptoms, but the defenseman participated in this practice. Will he play? An Islanders spokesman said they will see how he’s feeling on Thursday.