Kyogo Furuhashi scored on his first start as Ange Postecoglou got his Celtic reign up and running in the Czech Republic.
Japan international Furuhashi scored Celtic's second goal in a 4-2 first-leg victory over Jablonec in the Europa League.
Another summer signing, Liel Abada, had opened the scoring early on and both James Forrest and Ryan Christie restored Celtic's two-goal cushion in the second half after their defensive frailties reared their head again.
Postecoglou's first win in four matches in charge of Celtic put his team on course to face AZ Alkmaar in the play-offs.
The Australian handed Joe Hart a debut 24 hours after the goalkeeper completed his move from Tottenham, while Furuhashi was preferred to Odsonne Edouard up front.
Celtic should have been ahead before Abada's 12th-miute opener. Anthony Ralston set up David Turnbull for a free shot 14 yards out but the midfielder failed to properly get hold of his shot and the keeper got down to hold.
Hart made his first save a minute later with a comfortable hold from a header after Nir Bitton put off his marker at a corner.
Celtic soon took the lead. Forrest played the ball inside to Greg Taylor and the left-back's low cross was swept home by Abada after his initial effort was blocked.
Hart made a near-post stop and Abada had another effort saved before Celtic went two up inside 16 minutes.
Furuhashi set himself up with his first touch from Bitton's through ball and he dinked the ball over the goalkeeper.
The hosts responded inside 60 seconds. Vaclav Pilar ran in between Bitton and Carl Starfelt on to a lofted through ball and knocked the ball past a static Hart.
Celtic were looking confident in possession in the home half and Callum McGregor fired inches wide from 22 yards before Abada forced another first-half stop.
Furuhashi missed a glorious chance early in the second half when he volleyed well over from four yards after Abada's cross had deflected off the post.
Jablonec were getting balls into the box though without testing Hart and Celtic got the third in the 64th minute after Turnbull's ball over the top put Abada in behind. The Israeli had to check back but got a decent effort on target which the goalkeeper parried into the path of Forrest, who finished high into the net.
Forrest missed a more difficult chance before Celtic's defence were caught out by a ball down the left to Tomas Malinsky. The Jablonec player chipped Hart, who got a hand to it, but the ball came off the post and hit Bitton and went in.
The goal gave the hosts hope but Forrest crossed for substitute Christie to steer home a diving header in the 90th minute.
