Tom Barrasso's men took on Flames at Sheffield Arena, after the same team put them out of the Challenge Cup quarter-final on Wednesday.
The South Yorkshire side came back from 0-2 down to win with a dramatic late goal in regulation time.
With Matt Climie left out, Jackson Whistle returned in goal, which meant Anthony DeLuca was recalled to the squad.
Steelers, having lost their last two matches, need to get on a run before the season starts going completely sour.
But they were over-run in the first period.
Guildford, whose players support each other so well, easily added a second powerplay goal when TJ Foster sent a peach off a pass for Brett Ferguson to bury past Whistle.
Paul Dixon's team, in full flight, is a sight to behold and John Dunbar twice could have added to their haul.
But Steelers dug deep and showed some resolve to kill a long five-on-three penalty.
And once they'd emerged that kill, they scored, John Armstrong's shot deflecting off Jesse Craige's stick and past Chris Carrozzi.
A spot of late power play couldn't deliver the goal they were looking for, before the second break, but at least Sheffield were the dominating team.
Sheffield desperately through everything they could at the opposition defence, but possession was often lost at the critical time.
Mark Matheson and Ben O'Connor were grossly overworked as they tried to pilot the offensive drive from deep.
But it was another defenceman Josh McFadden who made it 2-2, at 52;57, motoring down the left flank and shooting across Carrozzi and under his blocker.
Josh Pitt failed on a chance to win the game with a breakaway with two minutes remaining.
But a power play followed and Pitt made sure he didn't miss again when the opportunity arose, at 59;36, to claim both points.