Massimiliano Allegri says it is more important for Juventus to be "effective" than "beautiful" after a 2-0 Serie A win over Spezia.

Dusan Vlahovic scored another stunning free-kick and new signing Arkadiusz Milik opened his Juve account to seal the victory in stoppage time on Wednesday.

There were boos from frustrated Bianconeri fans as Allegri's side showed they are a work in progress on a day in which they signed midfielder Leandro Paredes from Paris Saint-Germain.

Juve were sloppy in possession after a strong start, but Spezia lacked the quality to make them pay at Allianz Stadium, where the Turin giants maintained their unbeaten record this season.

Allegri called for patience, but made it clear that securing three points in more important than fluent football.

He told Sky Sport: "Now it is important to bring home the result, then there are games in which you play better. It is normal that we have to grow. 

"Last year Juventus did not win anything, we need everyone's help. It's right that they [the fans] boo us if things go wrong. There is a difference between being beautiful and effective: you have to be effective. I don't like being 'pretty' and not winning."

Juve face an anxious wait to discover the extent of an ankle injury sustained by goalkeeper Wojciech Szczesny, but Allegri confirmed he did suffer a fracture.

Serbia striker Vlahovic scored a carbon copy of his free-kick in the draw against Roma last weekend and now has four goals in as many games, but Allegri says there is much more to come.

He added: "Vlahovic fought, scored an extraordinary goal and worked well. He has room for improvement, I think this was his best performance.

"Vlahovic has improved, he could have scored more than one goal and I think he will be able to reach the maximum when he finds more control and tranquillity. He attacks the area and is a goalscorer, but he has to improve in other aspects. different cleanliness of the game."