The winning score came fo the Irish deep in injury time with extra time beckoning.
Ireland had seen their 19-7 lead steadily eroded and the sides were tied 19-19 as the play entered the seventh minute of injury time. Ireland then won a linrout to start a phase of play that saw backs and forwards handle before Lane took the ball on the right wing, survived a strong tackle to score the winning try.
The game was played in stifling heat and the sides were level at the break, seven points apiece, Ireland's try coming from Glen Telford in the 33rd minute with the conversion by out-half Michael Rainey.
The Italians levelled on the stroke of half-time but Ireland raced into a commanding lead with tries from Ciaran Potts and Conor O'Loughlin in the 45th and 53rd minutes respectively.
Italian full-back Mirco Bergamasco began the fight-back when he barged his way over for a try in the 57th minute and number 8 Sergio Parisse scored his side's third try when he got over with the help of his pack with four minutes of normal time remaining.
Andreo Brancoli levelled with a fine conversion from wide out but the Irish refused to be denied and showed remarkable determination to claim a victory that earned them ninth place at the conclusion of the competition.
IRELAND. T Bowe; K Matthews, B Murphy, G Telford, J Hearty (R Lane half-time); M Rainey capt, C McLoughlin (D Geraghty 75 min); J Moran, R Best (K Corrigan 13-19 min blood), D Fitzpatrick (E McGovern half-time); D Gannon, N McComb; J Muldoon (M McCornish 69 min), N Ronan; C Potts.