Romelu Lukaku ensured Napoli maintained their one-point lead at the top of Serie A with the only goal in Sunday's 1-0 win over his old club Roma. Belgium striker Lukaku poked home his fifth Napoli goal from Giovanni Di Lorenzo's low cross seven minutes after half-time in Naples, handing veteran Claudio Ranieri a defeat on his return to management with his boyhood club Roma. Napoli lead Atalanta, Inter Milan, Fiorentina and Lazio by a point -- with Juventus four points off the pace in sixth -- in a crowded title race which is yet to offer up a clear favourite for the Scudetto.