David Flitcroft identified his centre-half pairing as the key factor in a 0-0 draw at Crystal Palace which kept Barnsley outside the drop zone.
A forgettable game was overshadowed by a pre-match row over Barnsley's kits, which were both rejected by the referee - forcing the visitors to play in Palace's away strip.
In the end both sides finished with a point, and Flitcroft's side remain out of the relegation places by the same margin.
He said: "I think the experience of Stephen Foster and Bobby Hassell marshalled Glenn Murray really well which you have to do, he is the best striker in the league.
"Having two experienced heads in there helped us and it is important down the centre of pitch that you have leaders."
On the kit fiasco he said: "There was a bit of a stand-off before the game as I didn't want my players to not have the Barnsley badge, something they play for every day.
"But you realise the sense is probably to listen to the referee and I think it was the right decision.
"He asked us if we could wear our warm-up tops which I didn't think was appropriate so we decided to go with Palace's kit.
"The club has done everything it could before the game to make sure we had this situation right. We spoke to referees in the week and made sure they were happy with the kit and then we got here at 1.30pm and it was all change."
Lee Holmes put Preston ahead seven minutes before the break and Nicky Wroe doubled the advantage after 78 minutes after pouncing on goalkeeper Eirik Holmen Johansen's error.
And King wrapped up the win in stoppage time when he headed home to make it five home games unbeaten to leave the visitors languishing in the drop zone.
The home side took the lead when Holmes slotted under Johansen after a neat cutback from Stuart Beavon.
Beavon looked lively on his return and made space for a 20-yard effort shortly after the break but it never troubled Johansen.
Scunthorpe's Akpo Sodje wasted a chance on the hour, Declan Rudd missing a looping cross but the former Preston striker sliced his shot off target.
And the Lilywhites doubled their lead with Wroe firing into an empty net from 40 yards after Johansen botched his attempted clearance.
King saw a shot hit a post in the dying minutes in a goalmouth scramble but he got on the scoresheet in stoppage time, nodding in Jeffrey Monakana's cross to seal the win.
