After drawing at Dundee United on Sunday, the league leaders took time to get going but the breakthrough came in first-half injury time when Aston Oxborough collided with Hyunjun Yang to give Celtic a penalty.

Arne Engels stepped up and slotted into the bottom-left corner, sending the Motherwell keeper the wrong way.

Celtic had enjoyed the better chances in the first half, most notably when Daizen Maeda's strike was blocked by Oxborough, and although the Motherwell goalkeeper almost sent the ball into his own net, he and his defence scrambled it clear.

Brendan Rodgers' side escaped an early second-half scare when Tony Watt turned his back on Tawanda Maswanhise's shot right on Kasper Schmeichel's goalline and deflected it behind for a Celtic goal kick.

The hosts struck again when Engels' corner was flicked on by Liam Scales and rocketed into the back of the net off the head of Daizen Maeda.

Nicolas Kuhn got the third when his low shot from just outside the box was deflected off Motherwell's Kofi Balmer and flashed into the far corner.

And Reo Hatate added the fourth with a similar strike as he fired low into the other corner beyond the stretching Oxborough.