The Reds No.13 scored two brilliant solo tries as a storm pounded Brisbane's Suncorp Stadium.
Her efforts helped them come from 10-3 down to lead before play was halted with 20 minutes left with lightning in the vicinity.
Officials allowed 30 minutes for the lightning to pass, some strikes towards the end of that period beyond the 5km stadium radius allowed by World Rugby not enough to dissuade them.
Scores didn't change in the final period, the Reds moving to 3-0 and Brumbies 0-3 after tight losses to last year's grand finalists Fijiana Drua and the NSW Waratahs to begin the season.
Former high jump and triple jump talent Dascombe was the star for the hosts, the Toowoomba product breaking the line, busting a tackle then beating two more defenders to score a breathtaking first try.
She then charged down a kick, soccered the ball twice and collected cleanly for her double just after halftime that proved decisive.
The Brumbies opened the scoring with a penalty before lock Tabua Tuinakauvadra picked up the ball and darted from behind the ruck, spinning through a tackle and crashing over against the post.
They led 10-3 before Dascombe produced something from nothing and a late Cecilia Smith penalty gave the Reds a 13-10 lead they didn't let slip.
"That was one heck of a battle out there, first game I've played that's had a bit of a stoppage," Reds captain Shannon Parry said.
"They came in and ran with us for the full 80 (minutes)."
Brumbies captain Siokapesi Palu lamented some "silly mistakes" that spoiled their solid build-up.
"That skill execution is letting us down, but compared to previous years we're laying the foundations for the years to come," she said.
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