Kaapo Kahkonen made 34 saves for the Sharks (2-11-1), who were coming off their first two wins of the season.
“They were better; we were not good enough,” San Jose forward Mikael Granlund said. “They were winning way more puck battles, obviously put us on defense quite a bit, so we got to be better.”
Pietrangelo gave Vegas a 1-0 lead 1:00 into the first period with his first goal of the season, scoring on a wraparound.
“Right from the get-go, we looked flat for sure,” Sharks coach David Quinn said. “Getting down again 2-0 certainly didn't help our cause. We were just half a step behind all night long.
“We defended way too much and weren't able to end plays. We're chasing the game really from the drop of the puck.”
Martinez made it 2-0 at 11:19 of the first, one-timing Amadio’s pass from the point.
“Will [Carrier] screened the goalie and ‘Marty’ found a way to get it in,” Amadio said.
Karlsson extended it to 3-0 at 2:24 of the third period with a short-handed goal. Martinez pushed it to 4-0 at 4:40 with his second goal after scoring from the left circle.
“It was a good play,” Martinez said. “‘Petro’ did a really good job of [reeling] that guy in and giving me more time and space. I was more surprised at how much time I had. So, I looked backside, and there wasn't really anyone there, so I figured I'd take the shot, which went in.”