Cardiff Devils recorded their 10th straight win and 30th of the season - but were made to fight for it at Sheffield Arena.
They were 2-0 up after 26 minutes but conceded two in the middle period.
Steelers can count themselves unlucky a third 'goal' was disallowed.
Steelers had held Cardiff, whose 5-2 win over Belfast Giants on Sunday took them nine points clear at the top of the league, in the early stages.
But then the champions clicked into gear and top scorer Charles Linglet fashioned two chances, one clattering the pipework.
When Tom Zanoski took a penalty, Cardiff executed ruthlessly, Joey Martin making and then scoring the opportunity at 9:15.
Tanner Eberle, Jonas Westerling and Robert Dowd brought energy for Steelers, but they were fortunate when Sean Bentivoglio twice hit the post.
Cardiff then won a battle for the puck in their own zone, broke quickly and Jake Morissette made it 0-2, at 13;17.
Tom Barrasso's boys showed character though to wipe out their advantage in seven glorious minutes.
First John Armstrong circled across the left flank and threw in a speculative shot which squirmed under Ben Bown's pads.
Jackson Whistle made to great saves and that provided a platform for Steelers' equaliser.
Ben O'Connor sent a puck goalwards and it presented itself for Jonathan Phillips to gently backhand in.
It was reward for a gutsier performance and they should have had a third. Mark Matheson planted the puck home but Armstrong, shoved from behind, was harshly called for goalie-interference, much to the anger of the crowd.
Sheffield took self-belief into the third session and that brought them the same level as Cardiff, which is no small achievement for a team that's struggled for so much of the year.
They forced several turn-overs and a deflected Dowd shot could have put them ahead.
But Gleason Fournier's deflected wrist shot hit the roof of Whistle's net with four minutes left.