Stars forward Denis Gurianov scored on the power play in overtime to seal the 3-2 comeback victory. The opportunity came after Golden Knights blue-liner Zach Whitecloud took a delay of game penalty when he shot the puck over the glass in the defensive zone.
Vegas held a 2-0 lead early in the third period before Stars captain Jamie Benn cut the advantage in half. Round 2 hero Joel Kiviranta netted the equalizer in the dying minutes of the final frame to send the game to overtime.
Dallas netminder Anton Khudobin made 34 stops on the night, strengthening his case to be a Conn Smythe candidate at 34 years old.
The Stars will participate in their third Stanley Cup Final in franchise history. They defeated the Buffalo Sabres in 1999, then fell to the New Jersey Devils one year later.
Dallas awaits the winner of the Tampa Bay Lightning-New York Islanders series, which Tampa currently leads 3-1.