After a scoreless - and relatively low-event - first period, the Islanders broke the game open with goals from Lee and Nelson 1:02 apart early in the second period.
The momentum started building from puck drop, with the Mathew Barzal line wheeling and creating chances in the Sabres' end. Cody Eakins' holding call put the Islanders on the power play, and while Lee's goal at 5:13 it came six seconds after the penalty expired - the pressure was born on the man advantage.
Like they had on Saturday, the Islanders rode the wave, with Nelson following up two shifts later, sniping his eighth of the season past Johansson at 6:15. The goal was Nelson's second in as many games and first of two on the evening.
The two-goal spurt gave the Islanders a cushion to fall back on, but instead they continued to press, with Cizikas making it 3-0 at 16:56, finishing off a backdoor feed from JG Pageau. The assist was Pageau's 200th-career point and showcased some nice chemistry between the two, as Pageau skated alongside Cizikas and Cal Clutterbuck for a couple of shifts in the second.
The three-goal output in the second period marked the second-straight game the Islanders broke open a game in the middle frame, as they scored four second-stanza tallies on Saturday.
Despite the 3-0 lead, the Sabres didn't go away quietly. Skinner scored his first goal of the season to make it 3-1 at 5:41, with Miller sneaking a shot through Sorokin at 9:35 to make it 3-2. Miller's goal put a little urgency back in the Islanders, who went up 4-2 on a Cal Clutterbuck partial breakaway that the vet backhanded top shelf past Johansson. Nelson iced the game with an empty-netter at 17:48.
Cizikas said the Islanders showed their bend, don't break mentality, while Trotz said the third period response was indicative of how his team doesn't feel the squeeze in a tight game.
"We got comfortable when the games get close," Trotz said. "We got a little quiet for a second there, but I liked our response. Through the weekend, our response was really good."