The Scottish Premiership title holders look destined to retain their crown after stretching their lead at the summit to 24 points courtesy of Commons' treble.
Neil Lennon's side did not have it all their own way in a tight first-half at Rugby Park, but Commons struck twice in two minutes after the break to send them on their way to three points.
His first arrived on 57 minutes after strike partner Lee Griffiths had teed him up, and the second came shortly after following a one-two with Adam Matthews.
Commons was initially denied a hat-trick by the linesman's flag 15 minutes from time, but shrugged of that disappointment to fire home from the edge of the box in the 86th minute.
The result will banish memories of Celtic's last away trip at the end of February, when Aberdeen sprung a shock to end their unbeaten run.
Kilmarnock, meanwhile, appear certain to finish in the bottom six with just three games remaining until the league splits in two for the final five matches of the campaign.
