The visitors raced into a 3-0 lead but were pegged back to 3-2 before the break, and it was not until a late double that they were able to breathe easy ahead of Tuesday's visit of Barcelona.
Veteran striker Kris Boyd threatened twice early on as the hosts began in enterprising fashion but a devastating burst of three goals in eight minutes took the wind from their sails.
First, Craig Samson flapped at Samaras' cross and Kris Commons (20) found the unguarded net and when the ball broke for Samaras at the far post, the Greece striker side-footed home his first league goal of the season (24).
Samaras, revelling in his deep-lying role, promptly worked a neat one-two with Commons and cut through the heart of the Killie defence to tuck home the third (27).
But Kilmarnock grabbed a lifeline via the boot of Sammy Clingan (35), the midfielder firing a venomous 22-yard free-kick past Fraser Forster's despairing drive.
Three minutes before half-time, the hosts had pulled back another when Sean Clohessy (42) and Michael Gardyne combined tidily for the former to pick his spot from 12 yards.
Teemu Pukki rattled the top of the crossbar as Celtic looked for some breathing space, while Forster was happy to gather any set pieces fired into his box during a less frenetic second period.
Samaras (88) finally settled Celtic nerves with a stooping six-yard header and there was still time for substitute Amido Balde (90) to scamper clear and pouch his first goal for the club with a low drive.