Pjanic scored one and set up another to put Juventus firmly in charge at half-time. Paulo Dybala and Dani Alves sealed matters after the break.
After a massive outlay on new players, a sixth successive Serie A title seemed a foregone conclusion for Juventus, while great things were also expected in the Champions League from the Turin club, who were runners-up in 2015.
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Juventus lead Serie A but it has not all been plain sailing for Massimiliano Allegri’s men, and they slogged through a goalless draw at home to Sevilla in their opening match in Europe’s elite club competition.
“We’ve been together for 40 days and we’re working well, but we need a bit of time because there are new players to fit in,” Allegri said.
“The risk this year is that we break with tradition: There could be the illusion that, having signed great players, we can easily win all the matches. Instead, we have to keep our usual attitude. Keeping our feet on the ground is the most important thing, not losing sight of our aims and working hard.”
Juventus are already without several key players because of long-term injuries and there were fears another would be added to the list when Pjanic, who had to receive treatment following an early challenge, was substituted at half-time.
But the Bosnia midfielder, who signed for €32 million (Dh131.7m) from AS Roma, is confident of recovering in time for the weekend.
“Today we were better at finding spaces, we followed Allegri’s instructions and you saw the results,” Pjanic said. “I took a knock on the calf, but I hope to recover as soon as possible and be on the pitch at Empoli.”
Juventus dominated from the start and broke the deadlock on 24 minutes after Zagreb defenders Gordon Schildenfeld and Leonardo Sigali got in each other’s way. Sigali attempted to head Leonardo Bonucci’s ball back to his goalkeeper, Pjanic nipped in behind and slotted the ball into the bottom right corner.
Schildenfeld almost immediately atoned for his error with Dinamo’s best chance of the match but headed Domagoj Antolic’s free kick onto the crossbar with Gianluigi Buffon beaten.
Pjanic helped Juventus double their lead in the 31st with a stunning pass for Higuain to chest down and volley into the bottom far corner.
Higuain transferred from rivals Napoli for €90 million after scoring 36 goals last campaign to break a 66-year-old Serie A record.
Zagreb were offering little resistance and Dybala extended Juve’s lead with a stunning strike, sending the ball swerving into the top near corner from more than 30 metres.
Dani Alves, another summer signing, had done little of note all match but he got on the scoresheet five minutes from time with a deflected free kick.
Dinamo goalkeeper Adrian Semper was wrongfooted by the deflection and although the 18-year-old managed to get a hand to the ball, he couldn’t keep it out.
The only moment for Dinamo fans to cheer was when former player Marko Pjaca, who scored 12 goals for the Croatian side last season, came on as a substitute in the 68th minute for Juventus.
Pjaca, who is yet to score for Juventus, also helped Zagreb reach the group stage with two goals in a preliminary round match against FK Vardar.
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