Celtic stormed into the Scottish Cup quarter-finals with a 5-1 win over St Mirren after a late flurry of goals at Parkhead.Tireless forward Daizen Maeda opened the scoring from close range in the 16th minute but the visitors, the only domestic side to beat Celtic this season, showed some spirit and ambition.However, substitute Reo Hatate netted from the penalty spot in the 76th minute after Buddies defender Richard Taylor was sent off by referee Steven McLean for conceding the VAR-confirmed spot-kick with a hand to prevent a certain goal.Fellow sub Oh Hyeon-gyu slammed in his first Celtic goal in the 80th minute before Stephen Robinson's side reduced the deficit with a Mark O'Hara penalty.Ange Postecoglou's side, as always, kept going and substitute Matt O'Riley fired in from the edge of the box before Hatate added a fifth with a similarly impressive strike in added time. FULL MATCH DETAILS The treble-chasing home side, with midfielder David Turnbull in for Hatate, made their usual swift start.There were only a couple of minutes played before Saints, who had Taylor and Declan Gallagher back for Charles Dunne and Greg Kiltie, had Trevor Carson to thank for the first time.The Buddies keeper parried a powerful drive from Portuguese winger Jota past the post for a corner which failed to trouble the visitors.The Paisley side tried to push forward but trouble was never far away and in the 11th minute Maeda shanked a cross only to see it rebound off Carson's far post.Fellow Japanese forward Kyogo Furuhashi went off with what looked like a shoulder injury to be replaced by winger Liel Abada with Maeda moving through the middle.Moments later he was in the right place to convert Aaron Mooy's cross for the opener, after the