Inverurie Locos joined Brora Rangers in second spot on the 27-point mark with several of the leading teams now concentrating on Scottish Cup action this Saturday.
Manager Neil Cooper highlighted the ordering off of his captain Neil McLean and how well his side reacted to the setback.
He said: “It was a harsh decision in my opinion.
“Neil got to the ball first, it was his momentum which took him through.
“There had been little between the sides in the first half, but I take my hat off to the players.
“Their workrate was fantastic, the ball was passed around better.
“Our first goal from Mark Souter was a great one although we were bawling at him from the touchline to pass the ball. He kept going for a great finish.
“For the second, the penalty was well despatched by Andy Hunter then Chris Angus took his two goals well to give us a good cushion.
“There was no point in us just having a lone striker just chasing the ball down. He did his job well, putting pressure on both central defenders and shuffling over to trouble their full back too.
“Ryan Stott made a difference as well when he came on, and I’m really pleased we’ve recorded a second successive clean sheet. It’s a big result for us as there’s a lot of teams up there at the top.”
All the goals came in the second half. Almost right from kick off left back Mark Souter made a marauding diagonal run and from the right side of the box his 14 yard drive beat Greig Simpson.
Nine minutes later the Red and Blacks were reduced to 10 men when McLean, who had been cautioned in the first half, was deemed by referee Dan MacFarlane to have shown his studs in a challenge on Craig MacAskill.
Despite their disadvantage the home team increased their lead soon after. Ex-Locos utility player Marc Young made a clumsy challenge on Chris Angus and Andy Hunter converted the spot kick by sending the goalkeeper the wrong way.
Angus added a late double for Locos and a miserable afternoon for the Kynoch Park team was complete when former Cove Rangers and Locos forward Michael Selfridge also collected a second yellow late on in the game.
Keith boss Dean Donaldson said: “I know how the game got away from us, as we’re too easy to get the better of.
“Our centre halves were excellent in the first half then in the second they decided they’d get pushed about
“The left back went past three of our players for their opener and I’d expect somebody to make a tackle. The players were weak.”