Sebastian Tounekti scored his first Celtic goal as the holders eased past Partick Thistle into the Premier Sports Cup semi-finals.
The Tunisia international followed his man-of-the-match debut at Kilmarnock with another impressive display capped off with a goal inside 60 seconds of the second half at Firhill.
The visitors were two in front by that stage thanks to headed goals within two minutes from Yang Hyun-jun and Liam Scales.
Thistle had some decent moments in the second half before substitute Luke McCowan rounded off a 4-0 victory.
The Jags had won eight of their 10 matches since former Celtic defender Mark Wilson took sole charge of the Championship side in the summer and Hoops manager Brendan Rodgers named a strong side for the Glasgow derby.
Viljami Sinisalo was handed the gloves while Kieran Tierney came back in to play his first full match since his summer return.
Yang started in front of Michel-Ange Balikwisha and Kelechi Iheanacho was handed a first start as Daizen Maeda was afforded a rest from the beginning ahead of Wednesday’s Europa League opener against Red Star Belgrade in Serbia.
After the Celtic fans continued their protests against the board with thousands of posters and chanting, their team pinned Thistle in from the start. Tierney, Callum McGregor and Iheanacho were off target from half-chances before Tounekti forced the first save.
The deadline-day signing was involved in the 26th-minute opener, playing a through-ball for Benjamin Nygren, who stood up a cross to the back post. Yang’s header squeezed inside the post after hitting off Thistle left-back Paddy Yeading.
Nygren soon produced a second assist when he crossed following a short corner. Scales met the ball at the corner of the six-yard box but managed to steer his header high into the net despite Lewis Budinauckas getting hands to the ball.
Reo Hatate could not find the target from another good chance after Yang did well to reach the byline and cut the ball back.
Celtic put the game well out of sight when winger Tounekti collected an excellent return pass from Iheanacho and slotted home.
Iheanacho drew a good diving save with a 25-yard drive while Ben Stanway proved Thistle’s biggest goal threat. The midfielder shot not far over from 20 yards and forced a decent stop from Sinisalo with a header.
McCowan slotted home in the 84th minute after fellow sub Balikwisha won the ball deep in the Jags half and both Maeda and Balikwisha threatened in the closing stages.
