The four-try blitz, after two games without their offensive mojo, was achieved not via the conventional manner of using the stiff breeze, but through their usual run and gun game which rocked Canterbury.
The visitors looked strangely off colour on attack, mainly due to 14 handling errors. They also kept some of their powder dry by subbing Jack Goodhue, Ben Funnell and Luke Whitelock with a quarter of the match left to run.
"A lot of that (second half) was down to that first half defence," said Steelers coach Darryl Suasua, who acknowledged that Canterbury will be a very different side in personnel and mindset should they face them again in the semis.
"We were bullied a bit in that first half, which no one likes. Our body height was a bit high."
Counties Manukau will thus contest their first playoffs rugby since the 2013 Premiership. This was also their first victory over Canterbury since 1998 and they will hope they can still finish third to avoid a trip to Christchurch. It caps a regular season where they have beaten franchise bases Auckland, Canterbury and Waikato.
For third place to transpire, the Steelers will need Tasman to not win a bonus point victory in Nelson today against the Southland Stags.
Steelers No 7 Jordan Taufua, the clash's outstanding figure, will be hoping his old Tasman Makos team don't get up, but he was just soaking up a red-letter victory.
"We knew we had to weather the storm and build the pressure. In the second half we just played our Steelers footy," he said.
"We don't mind whoever we play, as long as we bring the energy we brought today. We know semifinals is a whole different level and we know that Canterbury will be hurting and keen to put out a big one for their fans, but we're looking forward to the challenge."
The Steelers were not quite on point in a mediocre first half, though they did lead 7-6 at the break. They could not gain any field position in the first quarter, and missed more than their quota of tackles, while their set-piece came under fire. First five Piers Francis struggled with the trajectory of two of his touch-finders, which did not go out. Two shots at goal were spurned.
But Canterbury could not convert their field position, other than penalty goals to fullback Jordie Barrett, as they contrived to drop the ball eight times in the first half alone, before Steelers wing Toni Pulu dived over from close range for the first of his two tries in a fine outing.
Canterbury hooker Ben Funnell was binned and the Steelers set themselves to use the conditions to their advantage in the second stanza. Wing Sione Fifita was, however, harshly binned for knocking the ball down.
The Steelers poured the pressure on, led by the ubiquitous Taufua, who charged around like a rhino, and his cohorts such as Augustine Pulu and Pauliasi Manu. The only downsides were head knocks to captain Jimmy Tupou and Francis, both of whom left the field. Lu Laulala slotted in well to No 10 and was able to get the backline humming.
Counties Manukau 33 (T. Pulu 2, P. Manu, C. Vaega, R. Judd tries; L. Laulala 3 con, P. Francis con), Canterbury 21 (D. Lienert-Brown, N. Earle tries; J. Barrett con, 3 pen). HT: 7-6.