Coach Filippo Inzaghi returned to his former Bologna club and watched his Benevento side recover a 1-1 draw in the snow that leapfrogged the hosts in the Serie A table.
Inzaghi was fired by Bologna in 2019.
Bologna made a perfect start when the unmarked Nicola Sansone scored after 55 seconds on Friday, pouncing on Musa Barrow's blocked shot.
Bologna dominated the first hour in thickening snow.
Ginaluca Caparari missed an equaliser before halftime when he hit the post, but Nicolas Viola claimed it in the second half with a brilliant back-heeled flick after a mistake by goalkeeper Lukasz Skorupski.
The teams swapped places in the standings with Benevento moving up to 13th and Bologna going down to 14th.
Leaders AC Milan play at promoted Spezia on Saturday after third-place Juventus visit Napoli.
Second-place Inter Milan host Lazio on Sunday.