It was the second time in the series the Kings scored a power-play goal in overtime. Iafallo scored the winner in Game 1 at 9:19 of overtime after Anze Kopitar tied the game with a power-play goal with 17 seconds remaining in regulation.
The Kings lead the Stanley Cup Playoffs with 15 power-play opportunities so far, having converted on four of them (26.7 percent). During the regular season, Los Angeles was fourth in the NHL on the power play at 25.3 percent.
"It's a tight-checking series, we knew that all along," Oilers captain Connor McDavid said. "It's breaks here and there, it's little calls here and there, and we haven't seemed to be getting any of the bounces. We had our looks, we had our chances, and they found a way to get a power play and they score in overtime."
The power play in overtime of Game 3 came after Oilers forward Ryan Nugent-Hopkins was assessed a slashing penalty for breaking the stick of Iafallo, who was cutting to the front of the net.
"He cuts across the middle, and you're trying to clamp down on his stick and not take a whack," Nugent-Hopkins said. "Obviously, I came down too hard and his stick might have broken. If you're the ref, you can't fault him for that. I come down too hard and break his stick, so maybe I got to be in a better position to not put myself in that situation."
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But also like Game 1, the Kings used the power play to tie the game after falling behind.
During the celebration of McDavid's second power-play goal of the second period, Oilers forward Leon Draisaitl was assessed an unsportsmanlike conduct penalty for slashing Kings defenseman Drew Doughty on the leg on the way to his teammates in the corner. 18 seconds later, Adrian Kempe took a long pass of the end boards and one-timed a slap shot past Stuart Skinner for his third goal of the series.
"The goal was huge. It was even better because in the first period we had a bunch of power plays and we really couldn't convert on them," Kopitar said. "We couldn't get anything going, so we set that play up and obviously, it worked out."
Said Draisaitl: "We can definitely be smarter. I took a bad penalty there, and that's on me."