Chelsea target Alex Sandro is "extraordinary" and will not be leaving Juventus in the transfer window, according to head coach Massimiliano Allegri.

Juve's general director Giuseppe Marotta confirmed last month the club turned down an offer for Sandro from the Premier League champions, who were reportedly willing to pay up to €60million.

Former Juve boss Antonio Conte, who is now in charge at Stamford Bridge, has been linked with a fresh bid for the 26-year-old left-back, who scored three Serie A goals last season as Allegri's men won the title for the sixth year in a row.

But Allegri is determined to hold on to Sandro, with the coach having already allowed one of his defenders, Leonardo Bonucci, to join AC Milan in a surprise deal worth €42m.

"Alex Sandro? He's a Juventus player, he's extraordinary and he won't leave us," Allegri said to Premium Sport after Juve beat Roma on penalties in the International Champions Cup on Sunday.

"He's improved so much since he came to Juve and he has the margins to improve again. Along with [Real Madrid left-back] Marcelo, he's the best in the world."

Juve have dominated Serie A under Allegri and his predecessor Conte but the incumbent expects there to be a wide-open race for the Scudetto when the new season gets under way on August 19, with the holders due to host Cagliari.

"This year will be much more difficult because all our rivals have strengthened," Allegri said. "It will be complicated and tricky to win the seventh consecutive league title, but this is our first goal of the season.

"Last season Roma got 87 points, a record in their history, and they will be the main competition, but Napoli, Milan and Inter will also fight for the title."