Ballardini replaced the sacked Stefano Pioli following Monday's 2-0 defeat at Catania, Bologna's third loss in four league games.
While no doubt happy to avoid defeat on his debut, the veteran coach knows better will be needed in the months ahead to turn around a run that has seen fourth-bottom Bologna win just three of their 19 games this season.
Lazio also have a new coach still bedding in after Edy Reja returned for a second stint at the Biancoceleste following the departure of Vladimir Petkovic last weekend.
Reja enjoyed a winning start as Lazio beat Inter Milan 1-0 on Monday, but was unable to make it back-to-back wins with his charges looking impotent against a disciplined Bologna backline.
The hosts did much of the early pressing with Alessandro Diamanti twice seeing decent strikes kept at bay by Etrit Berisha in the Lazio goal.
A nicely-worked Bologna move in the 28th minute almost ended with a sublime goal as Rolando Bianchi dragged a backheel towards goal but Berisha was again in the right place to make the stop.
Lazio were poor in the opening 45 minutes, producing only speculative efforts from Andres Dias and Antonio Candreva, and they barely improved in the second half, with Miroslav Klose's failure to turn home Candreva's cross from close range their only opening.
Yet as poor as the visitors were, they never looked in real danger of conceding.
Lazaros Christodoulopoulos' weak shot for the hosts was easily saved by Berisha, while Panaioutis Kone skewed wide with Bologna's final opening inside the last 10 minutes.