SALT LAKE CITY — Shea Theodore scored on a snap shot from the high slot with 51.5 seconds left in overtime and the Vegas Golden Knights beat the Utah Mammoth 5-4 on Monday night after squandering a three-goal lead, tying their first-round playoff series at two games apiece.

“We just didn’t quit,” Theodore said.

Game 5 in the best-of-seven series is Wednesday night in Las Vegas (10 p.m. ET/ 7 p.m. PT on Sportsnet and Sportsnet+).

The Golden Knights appeared to have won the game earlier in OT when Pavel Dorofeyev tapped in a loose puck with 9:41 left, but the apparent score was waved off when it was determined Vegas was offside.

“It was good we never stopped,” Theodore said. “It sucks that one got called back, but it was good to get it done.”

Vegas’ Brett Howden scored his second goal of the game on a tip-in with 9:35 remaining in the third period, and that forced overtime after Utah had stormed back with four straight goals.

“I liked the way we responded in the third after they scored,” Howden said. “We stuck with it.”

The Golden Knights raced out to a 3-0 lead with two goals in the first and one early in the second by Dorofeyev, Howden and Cole Smith.

Utah countered with four straight scores, capped by Clayton Keller’s wrist shot off a deflection for a 4-3 lead at the 5:10 mark of the third period.

“I’m proud of the way our guys responded to adversity,” Utah coach Andre Tourigny said. “It was a hard-fought game. We know how good they can be and I think we responded well in the second half of the game.”

Utah’s Karel Vejmelka stopped 31 shots. Carter Hart made 29 saves for Vegas.

Facing a three-goal deficit, Utah’s Nick Schmaltz and Ian Cole scored 29 seconds apart in the second period to set the Mammoth’s comeback in motion. Schmaltz got Utah on the board at the 8:04 mark, and Cole followed with a 50-foot slap shot at 8:33 of the second.

Michael Carcone tied it on another slap shot at 1:44 of the third.

Dorofeyev flicked home a wrist shot to put the Golden Knights in front just 72 seconds into the first. Howden then threaded another wrist shot past Vejmelka’s skate for a short-handed goal with 1:22 left in the period.

Smith’s tip-in at 3:27 of the second gave the Golden Knights their third goal.

“We started really well, lost ourselves for a bit,” Vegas coach John Tortorella said. “Momentum swung to their side, but we hung in there.”

Utah fell behind early after struggling to create scoring chances during the first period. The Mammoth tallied three shots on goal over the first 20 minutes. Only one came outside of a power play.

Vegas allowed 30 shots on goal over the final two regulation periods and overtime.