Newcastle do not look like a side battling for fourth spot in The Premiership and their UEFA Champions League hopes were dealt another blow as they were held at Leicester.
Leicester are fighting a vastly different battle to Newcastle and Paul Dickov's unerring finish put them in front.
However, Sir Bobby Robson threw on Ambrose and he nodded home from close range after Leicester failed to clear their lines.
Chances in the first half were at a premium, with Laurent Robert at the heart of Newcastle's good work.
The French flyer almost produced a spectacular goal on six minutes, but his acrobatic volley from an acute angle flew across the face of goal.
The two teams appeared to suffer from a post-Christmas hangover as there was disappointingly little quality on show, with the highlight being a speculative 40-yard free kick from Robert which forced Ian Walker to tip the shot over his crossbar.
Newcastle started the second half with a real sense of purpose and only a smart save from Walker prevented Robert from opening the scoring following a neat pass from Nolberto Solano.
All the questions were being asked by Newcastle's left flank as Robert had a free kick deflected over and from the resulting corner Olivier Bernard fired just wide from 20 yards.
Tresor Lomana Lua Lua flattered to deceive in the first half, with his play littered with elementary mistakes, but he almost made himself the hero of the piece when unleashing a wicked shot which left Walker helpless but flew inches wide.
Leicester forays forward were few and far between as Newcastle dominated but Muzzy Izzet kept Magpies keeper Shay Given honest with a header from the edge of the box and a drilled shot.
Newcastle's defensive frailties reared their head again as Paul Dickov fired The Foxes in front on 67 minutes after Aaron Hughes failed to clear his lines.
Newcastle struggled to fashion a response but Robson's tactical masterstroke reaped dividends in injury time as Ambrose pinched a late point for the visitors, making Les Ferdinand's missed header ten minutes from time look all the more costly for The Foxes.
