Six goals in the middle period for the Langley Thunder turned a one-goal deficit into enough of cushion to withstand the Victoria Shamrocks.
The result was a 9-7 victory in game one of the best-of-seven Western Lacrosse Association semifinal playoff series on Tuesday night in Victoria.
Game two is tonight (Thursday) at the Langley Events Centre.
Athan Iannucci paced the Thunder attack with four goals, while Brodie MacDonald made 39 saves.
The Shamrocks led 3-2 after the first period, but the second was all Langley.
Nick Bilic tied the score eight seconds in and less than a minute later, Alex Turner gave the visitors a lead they would not relinquish.
Iannucci scored twice more, to go along with his two first-period goals, and Mike Grimes and Rob Van Beek rounded out the second period scoring as the Thunder went into intermission up 8-3.
Victoria tried to claw back into the game in the third, but never got closer than two goals.
Jarrett Toll had Langley's ninth goal.
Game three of the series is back in Victoria on Saturday, with the fourth game on Monday at the Langley Events Centre.