The reigning champions can go seven points clear of the Dons for at least 24 hours if they defeat Hearts at Celtic Park on Saturday, with their closest rivals not in action until Sunday when they face Hamilton at Pittodrie.
Aberdeen slipped up in the last round of fixtures before the international break, losing 2-1 at Motherwell just hours after Tom Rogic’s 90th-minute goal earned Celtic a dramatic 1-0 win at Kilmarnock.
Celtic midfielder McGregor insists the time is right for he and his team-mates to press home their advantage and increase the pressure on Aberdeen.
“We know that we now need to kick on and we need to see what they [Aberdeen] have got and see if they can come back,” he said.
“Sometimes it is harder to do the chasing. We have got ourselves into a good position now. Aberdeen have had a great season and they will keep going on until the end. We need to match that as well. It’s important now that we get the international boys back this week, hopefully without any injuries, and really kick on.”