Lehner was pulled after the goal. He has never defeated the Hurricanes (0-5-0).
"I know myself, I felt really good coming in," Lehner said. "It was kind of a weird first period, but they came out flying in the second period, and that was that."
Trotz said of changing goalies, "Goals had been pretty hard to come by in this series, and we couldn't let it get past three. I just felt that hopefully it could quiet it down, maybe guys would focus in for [Greiss]. We just couldn't get close enough in the end."
The Hurricanes extended the lead to 4-1 at 8:51 after Jordan Staal lifted a pass to Williams, who scored on a backhand for his 100th playoff point (39 goals, 61 assists).
"We came out and imposed our will on them early (in the second period), scoring a goal," Williams said. "You just have to create doubt in them, and we did that at the start of the second and carried it on. And McElhinney, as usual, not surprised, he was there when we needed him, made some big saves and it was great."
McElhinney earned his third straight win since replacing the injured Petr Mrazek in the second period of Game 2.
"Obviously we knew it was going to be a tight game," McElhinney said. "To get a couple extra goals and sit with that lead going into the third felt great."
Andrei Svechnikov scored off the rush to make it 5-1 at 15:13 of the third period.