"We made some big errors on this trip and paid for it," Edmonton coach Ken Hitchcock said. "We played hard in all three games; I'm really proud of our effort. We did a lot of really good things. Unfortunately, at the turn of games, we were the one that made a mistake. Today was a perfect example.
"We were coming on strong, we were on the power play, it was 3-2. Thirty seconds after the power play we get scored on. It's unfortunate."
Pulock gave the Islanders a 1-0 lead with a power-play goal at 3:02 of the second period when he one-timed Toews' cross-ice feed from the left circle.
Lehner kept the Islanders in front at 8:08 when he stretched across his crease to get his right pad on Oscar Klefbom's rebound chance from point-blank range.
Filppula made it 2-0 when he redirected Nick Leddy's shot from the left point for his 12th goal of the season at 13:30.
"For us, it's important not to get discouraged," Oilers defenseman Darnell Nurse said. "Bring that hard-working attitude each and every day. We need to limit obviously the chances that we give up and find a way to get on the right side of the score sheet. We're doing a lot of things right, but at the same time we're not getting the results."