Juventus are dealing with a "mental issue" when it comes to scoring, according to coach Maurizio Sarri, who has been left disappointed by the lack of goals so far this season.

Sarri's unbeaten side sit top of Serie A, though they hold a slender lead over second-place Inter, whose only defeat came against the Bianconeri.

Juve drew 1-1 with Lecce on Saturday as the decision to rest Cristiano Ronaldo backfired, Gonzalo Higuain, Leonardo Bonucci and Federico Bernardeschi particularly wasteful.

Though they have conceded just eight goals in league action, the reigning champions are the lowest scorers in the the top four as they prepare to host Genoa on Wednesday.

"We are adapting to a new style of football, so it's only natural that it will take a little while to perfect. We can improve a great deal and are on the right track," Sarri told a pre-match news conference.

"The feeling is that we still have some more room for improvement and important potential to express ourselves.

"We have a very low average of shots finding not just the net, but the frame of the goal. In my view, it's more of a mental issue than anything else.

"I expressed my fear with the players about that and we'll try to prepare some training exercises to help, but we also need to be more determined in front of goal.

"We are still the best defence in Serie A. This league has changed, the average goals of all the teams has gone up and in general it is a more prolific competition.

"Besides, lately we conceded pretty much exclusively from penalties, so we need to keep an eye on those situations."

Juve could take on Genoa without Miralem Pjanic and Higuain after they suffered injuries against Lecce, though Douglas Costa may possibly make a return to action in the midweek fixture.

"Pjanic does not have a muscular lesion, but we'll see how he does. Yesterday, he was not in a condition to play," Sarri added. 

"Higuain had a violent knock to the head and was not in good shape yesterday, he had stitches and was shaken up, but again we'll see the situation today. If Higuain can't make it, then it's very unlikely we can make a 4-3-3 work.

"Costa is returning after 45 days out and only had one training session with the squad, but we'll see if he's able to play a few minutes."