Alvaro Morata gave Juventus a 21st-minute lead following a majestic cross-field pass from Federico Chiesa but Gaetano Letizia levelled for Benevento in first-half stoppage time, rifling home the ball after Arthur's poor clearance landed at his feet.
Juve's performance raised more questions about the team's dependence on 35-year-old Ronaldo who is their leading scorer in Serie A with eight goals despite having played only five matches.
Although they are still unbeaten in Serie A, Juve have yet to win a league game this season without Ronaldo and their performances have been laboured.
As with all the other Serie A games at the weekend, there was a minute's silence for Diego Maradona, who died aged 60 on Wednesday, and play was stopped for a tribute to the great Argentine in the tenth minute.
Federico Chiesa set up Juve's goal with a majestic cross-field pass to release Morata and the Spaniard glided past his mark and scored with an angled shot which went in off the post.
Paulo Dybala should have added a second but curled his shot wide before Benevento grabbed their surprise equaliser three minutes into first-half stoppage time.
Juventus goalkeeper Wojciech Szczesny made a brilliant save to deny Pasquale Schiattarella but the resulting corner was poorly cleared by Arthur and the ball fell perfectly for Letizia to rifle into the net.
Juventus had more possession in the second half but did little with it, while Benevento looked dangerous when they broke forward.
Benevento had six players booked and Juventus one in the second half before Morata lost his cool and was dismissed.