A BARNSTORMING final 20 minutes saw Celtic finally impose their will on opponents who, for long spells, threatened to undermine their credibility as championship contenders.
By full-time Tony Mowbray's side could have reached double figures with the number of openings they created.
As it was, they did enough to reduce Rangers' lead at the top of the table to seven points and they also have a winnable game in hand at Kilmarnock.
Celtic -- who began the match without a Scot in the starting XI -- allowed their hosts to dictate the tempo early on and they paid for their tentative start by falling behind in the 12th minute, Liam Craig scoring from the penalty spot after Steven Milne had been upended.
They may have been wretched during the opening 45 minutes but Celtic dominated after the break, helped in no small part by the instant dismissal of Saints defender Graham Gartland. He had already been cautioned for a first-half foul on Aiden McGeady when, 10 seconds after the restart, he brought down Marc-Antoine Fortune on the edge of the penalty area.
The equaliser came out of nothing. Substitute Paul McGowan released Samaras who, in turn, supplied Fortune. A cross seemed the most likely option but the Frenchman elected instead to shoot from the far corner of the penalty area and he managed to get so much power into his effort that the ball must have looked like a blur to Graeme Smith as it passed him on its way into the net.
Even so, when further goals did not follow immediately, anxiousness gripped the Celtic support. Mowbray, meanwhile, simply sent on more wingers and strikers, finishing the match with seven attacking players in his side.
Saints withstood wave after wave of Celtic pressure before Samaras emphatically volleyed them in front from a Josh Thompson knockdown with 14 minutes remaining.
Fortune secured the points when he sidefooted home the rebound after Smith could only parry a 20-yarder from substitute Paddy McCourt. Four of the striker's seven goals this season have come against the Perth club.
McCourt, a scorer of great goals rather than a great goalscorer, then drifted past two defenders before fin-ishing into Smith's top left corner.