Celtic have emphatically regained their nine-point lead in the Premiership.
They suffered a shock start when Saints took the lead with an Alex O'Hara penalty after a Greg Taylor handball that was confirmed by VAR - and it was a frustrating first half. However, when Charles Dunne was sent off just before half-time for pulling back Kyogo Furuhashi their task was made easier.
The introduction of Liel Abada at half-time was the catayst as he set up Jota for the leveller and the scored the third after Alistair Johnston had headed home the second. Matt O'Riley and Oh Hyeon-gyu, with a penalty, highlighted their superiority.