Juve's win was marred by a pre-match clash between Juve ultras and the team bus - and also Jonathan Zebina being slapped by one fan.
"We all know that we are not having a great year and this victory can not hide the problems," said Bettega. "Now we want to try to win back our fans.
"Even today we had so many absentees, but I do not want to diminish the responsibility of those who played. Now we will work in a relaxed manner, no longer having midweek commitments."