Substitute Georgios Samaras hit a late winner as Celtic came from behind to extend their lead over Rangers at the top of the SPL to eight points. Striker Chris Porter had put Motherwell in front with a header from Brian McLean's right-wing cross (60). But Scott McDonald levelled with a header from Shunsuke Nakamura's centre (62) before Samaras won it with a header from Barry Robson's corner (79). Celtic: Boruc, Hinkel, Caldwell, Balde, Naylor (Wilson 75), Nakamura (Scott Brown 65), Hartley, Robson, McGeady, McDonald, Vennegoor of Hesselink (Samaras 65). Subs Not Used: Mark Brown, O'Dea, Donati, Hutchinson. Booked: Robson. Goals: McDonald 62, Samaras 79. Att: 9,158 Ref: S Conroy