Victor Eklund and Ben Hutton scored for the Islanders (7-6-4), who have lost four straight (0-2-2). Sorokin made 37 saves.
"I don't know about the last four games. The Carolina game (a 5-3 loss on Thursday) was one of our best games of the year," New York coach Peter DeBoer said. "The New Jersey game (a 5-4 overtime loss on Saturday) was poor. I thought tonight we were better for stretches, but not long enough."
Hutton put the Islanders ahead 1-0 at 6:14 of the first period. Simon Holmstrom was at the right point and sent a diagonal pass down to Hutton, who had chipped down and beat Askarov's right pad at the back post.
Stenberg tied it 1-1 at 16:41. Ty Dellandrea knocked down Logan Stanley's clearing attempt up the boards, and Toffoli sent wrist shot from the top of the right circle that deflected in off the stick of Stenberg.
"[Stenberg's] so smooth and skilled, it's easy," Sharks forward Mason Marchment said. "Sometimes it's hard when you're young to come in with the confidence to carry it and hang on to it like he can. He's taking some strides. It's only been 20 games and he's only going to get better."