Steelers have the chance to defend their Play Off Championship after qualifying for the semi finals, courtesy of tight two-legged contest with Guildford.
At a sold-out Spectrum, they went down 5-4, the last Flames’ goal coming with 38 seconds on the clock. But the damage was done on Saturday, when Sheffield chalked up a 5-2 first leg quarter final victory, ensuring passage.
They now play Nottingham on Panthers’ home ice, the winner facing either Cardiff Devils or Fife Flyers in the final.
Steelers had gone into Sunday’s decider on the back of five consecutive wins featuring 26 goals and with a fully-fit squad allowing them to leave out two imports, Tim Wallace and Matt Marquardt.
Coach Thompson had told his team to win the game, rather than worrying about aggregate scores.
And they set about the task with gusto, going ahead within two minutes, when John Armstrong (asst Mathieu Roy) scored his fourth point of the weekend.
By 3;22 Steelers were 7-2 up on aggregate when Mark Matheson steered home a second of the evening, past former NHL draft pick Chris Carrozzi.
With Zack Fitzgerald sitting out interference and roughing penalties, Guildford opened their account with Jesse Craige scoring on the Power Play at 7:39.
With Andreas Jamtin serving a high sticks minor, Guildford pressed again, but Ervins Mustukovs pulled out a top drawer save to keep them ahead on the night - something that probably impressed Petr Čech, the Arsenal goalie watching the game.
Sheffield were on the rack but Ronnberg and Roy were leading by example in blocking shots - one followed by Jamtin and Miika Franssila.
Flames, who had lost Brett Ferguson to an EIHL suspension for a check from behind on Eric Neiley the previous night, got their teeth into Steelers 68 seconds into the middle period, Rhett Rachinski converting.
But that 2-2 scoreline lasted only 35 seconds; Colton Fretter notching his sixth point in four games (assts Matheson, Neiley.)
And Flames had a let-off when Robert Dowd struck the cross bar and a Levi Nelson effort was cleared off the goal line.
But their luck ran out when Neiley roofed a backhander for 4-2 at 33;44 (agg 9-4.)
Paul Dixon’s team must have felt they had little of making the Nottingham finals.
But Fitzgerald took four minutes of high sticking penalties into the last session - and his team were made to pay for it.
Ben Davies buried a chance at 41;34 and Kruise Reddick added another at 43;00, ex Steeler Geoff Walker and John Dunbar assisting.
That set an already charged atmosphere through the roof, with the expectations of home fans suddenly heightened.
Sheffield had to rediscover their composure and Roy and Dowd both tried in vain to restore the lead with a fifth away strike of the evening.
But it was now Flames that were the biggest offensive threat and Mustukovs had to be on his toes as forwards drove towards his crease time after time.
Sheffield upped the pressure on themselves by taking two penalties Fretter (Hooking) 48:08 and Jamtin (Holding Stick), at 50:03.
Just to make it that little bit harder, Davey Phillips took another minor (Holding) at 51:31 and Jamtin, back out of the box, hooked the puck off Mustukovs’s line.
Flames had tried to slow the game down in Saturday night’s (5-2) first leg and Thompson took the liberty of doing the same with a Time Out, in Surrey.
But the home side had the consolation of a 5-4 winner on the night, from Davies.