Another summer signing, LielAbada had opened the scoring. Ryan Christie, James Forrest, and James Forrest restored Celtic’s 2-goal cushion in half-time after their defensive frailties again reared their ugly heads. Postecoglou's win in his first four matches as Celtic boss put his team in position to face AZ Alkmaar during the play-offs. Joe Hart made his debut in Australia 24 hours after Tottenham goalkeeper Tottenham Furuhashi had left. Odsonne Eduard was preferable to Furuhashi at the front. Abada's opening goal in the 12th minute of the first half meant that Celtic should have led. Anthony Ralston placed David Turnbull 14 yards away for a free goal, but the player failed to grasp his shot properly and the 'keeper took control. Hart made his second save just a minute after Nirbitton's corner marker was pushed aside by Hart. Celtic quickly took control. After Forrest had blocked his initial attempt, Forrest lobbed the ball inside to Greg Taylor. Abada swept the low cross of the left-back into the net and he was soon in control. Hart made an excellent stop at the near-post and Abada was able to save another effort before Celtic scored two goals in less than 16 minutes. Furuhashi began by touching Bitton's through balls and then he dinked the ball above the goalkeeper. Within 60 seconds, the hosts had their response. Vaclav Pilar ran between Carl Starfelt, Bitton, and onto a lofted throughball. He then knocked the ball past Hart. Celtic looked confident and in possession in their home half, Callum McGregor hit inches wide from 22 yard before Abada forced an additional first-half stop. Furuhashi was denied a brilliant chance in the second-half when he hit a volley from only four yards after Abada crossed the ball off the post. Jablonec were getting ball in the box without testing Hart. Celtic got the third in 64 minutes, just after Turnbull's pass over the top had Abada behind. Forrest was able to score high and clear the Israeli goalkeeper. Forrest missed another chance, before Celtic's defensive were caught out when a ball down the right to Tomas Malinok was played. Hart was chipped and pushed by the Jablonec players, but Hart managed to get a grip on it. The ball hit Bitton and came off the posts. The goal gave hope to hosts, but Forrest replaced Christie with a diving header in 90 minutes. What did the manager say? Celtic bos Ange Postecoglou:"The result was clearly a positive. I believe it's crucial, especially for the players, as they have worked hard. Every competitive game we had the chance to win, but we haven’t. "It's rewarding for the players and hopefully gives em confidence and belief moving ahead. "The performance was good. The first half an hour was very impressive. We managed to control the game. I felt that we lost our focus a bit, particularly in the second-half, and lost complete control of the game. "We did okay in the second half, but we didn’t have the control we needed to win the game. "It's more than one aspect [of our defensive weaknesses]. Yes, we scored 4 goals, but had amazing opportunities to score more. "I felt like we didn't control it as well as possible after 35 minutes. "Yes, we were really open defensively, but we gave the ball away unnecessarily. We were simply making poor choices. When we did press, it wasn't as compact as we thought. "The game was left open to all aspects. Although we had some chances, it was not how I want us play." What's next Celtic face Dundee in Parkhead's Scottish Premiership match on Sunday, 3:00pm. Next Thursday, Jablonec hosts a return clash at home at 7.45pm.