The reigning champions took their opportunity to leapfrog Inter, who drew 1-1 with Torino earlier in the day, as Gonzalo Higuain and Juan Cuadrado denied the determined visitors their first top-flight points.
Benevento have now lost all 12 of their league games this season, but can take heart from giving the Bianconeri real difficulties at Allianz Stadium.
Roberto De Zerbi's side even took an unlikely first-half lead when Amato Ciciretti's free-kick left Wojciech Szczesny, in for the rested Gianluigi Buffon, rooted to the spot.
Although that was the visitors' only shot of the opening period, it took Massimiliano Allegri's men – wearing a special 120th anniversary kit – until the 57th minute to forge a breakthrough as Higuain coolly dispatched his fifth goal in four matches in all competitions.
Cuadrado then clinched the points with a close-range header to the relief of the home supporters, Juve now trailing Serie A leaders Napoli by only a point after their 0-0 draw at Chievo.
A dazzling early Douglas Costa dash down the left flank almost led to the opener as his low cross was parried awkwardly against the near post by Alberto Brignoli.
And Costa soon came close again – this time without the aid of the goalkeeper – rattling a left-footed strike against the angle of the upright and crossbar.
But the goal instead came at the other end. Benevento captain Ciciretti curled a free-kick around the wall and beyond the idle Szczesny, celebrating maniacally as the Allianz Stadium fell to a stunned silence.
Cuadrado should have drawn Juventus level when he ran through from Paulo Dybala's pass, but the Colombian blazed his effort over the top.
Brignoli then brilliantly stood tall to block from Dybala after he shimmied through the visiting back line, before the same man somehow shot wide when Higuain teed up a clear opening.
The keeper saved again from a Costa free-kick as Benevento incredibly survived the onslaught to take their lead into half-time, with Juve initially continuing to struggle after the restart.
However, the first big opportunity of the second half fell Higuain's way and he made no mistake, sweeping a pinpoint finish into the top-right corner from Blaise Matuidi's knockdown.
Brignoli persisted with his brave resistance as he denied Cuadrado's effort and then scrambled across his goal line to dive on Higuain's trundling rebound, before Matuidi nodded over.
But the turnaround was complete in the 65th minute, with Cuadrado meeting Alex Sandro's deep cross with a firm downward header that bounced up past Brignoli.
Danilo Cataldi's wonderful dipping effort almost restored parity, but that represented the extent of Benevento's attacking intent as only a smart Brignoli stop kept Dybala's replacement Rodrigo Bentancur from adding a late third.
