"We are very happy with Sarri. Things are set up for three years, the strength of his ideas will come with their continuation in time, and this is the priority.
"The first half of the season has been excellent, we are first in the standings and we passed the Champions League group stage in first.
"I will evaluate the season at the end, thinking that I can win in February is foolish, but being first today is a good starting point."
Juventus have won the last eight Serie A titles consecutively - last missing out to AC Milan, who had Allegri in charge at the time - but they're facing a serious threat this season, with Inter and Lazio both close to the top of the table.
On top of that, Juve are still waiting to end their 24-year wait for the Champions League.
They've reached five finals since they last won the trophy in 1996, but even following the arrival of Cristiano Ronaldo, the Bianconeri haven't been able to get past the quarter-final stage of the competition.
Juventus will carry on this season's Champions League campaign against French side