GLASGOW, Sept 21 (Reuters) - Rangers beat Motherwell 2-1 thanks to second half goals from Steven Davis and Nacho Novo on Sunday to stay three points clear of Celtic in the Scottish Premier League.
Celtic won 3-1 in a later match at Kilmarnock with Greek striker Georgios Samaras scoring twice before the champions were reduced to 10 men with two minutes remaining.
Rangers have 16 points from six games with Celtic in second place on 13.
David Clarkson hooked a late consolation goal for Motherwell but manager Mark McGhee was bitterly disappointed.
"I felt it was the worst performance that we have had since I have been at the football club," he said. "I have never felt as disappointed as I do today about a performance."
Davis clipped a neat shot over sprawling keeper Graeme Smith to give Rangers the lead on 56 minutes after Kenny Miller flicked on a long kick out by keeper Neil Alexander.
Spanish striker Nacho Novo bundled in the second in the 75th, just three minutes after coming on as a substitute for American midfielder DaMarcus Beasley.
Smith dived out to push away a low cross from Miller but the ball struck Novo as he slid in and it bounced back over the line.
"Motherwell came back into the game near the end and we have not handled that aspect as we should have and that is something to work on," said Rangers manager Walter Smith.
Shaun Maloney missed a 19th minute penalty for Celtic by slashing his shot wide of the right post but he made amends by curling in the opener from 18 metres seven minutes later.
Samaras then scored a magnificent goal after 56 minutes when he charged from the halfway line on the right and cut into the box before swerving a low shot around keeper Alan Combe from seven metres.
Samaras converted a penalty for 3-0 before Celtic defender Gary Caldwell was sent off for handling on the line to give Kilmarnock a spot kick.
Moroccan Mehdi Taouil cracked it down the middle and through the legs of Polish keeper Artur Boruc.