Despite the fact Juve were still chasing runaway joint leaders Roma and Napoli, coach Antonio Conte opted to rest in-form stars Arturo Vidal and
Carlos Tevez and it backfired as Cyril Thereau found his way through a sluggish visiting defence to open the scoring.
Fabio Quagliarella dragged his colleagues back into the game after the break but an under-par Bianconeri side were generally short on ideas and were lucky that the hapless Bernardini gifted them all three points.
Napoli were held to a 1-1 draw by bottom side Sassuolo, though, allowing Juve to take a share of second place while Roma moved two points clear at the top after beating Sampdoria 2-0.
It was a slow start at the Bentegodi and it took 14 minutes for Alberto Paloschi to try his luck, only for Giorgio Chiellini to make the block.
Fernando Llorente's sighter at the other end lacked accuracy but the build-up play was impressive and Juve came knocking again with Paul Pogba leaping at a Federico Peluso cross.
The visitors continued to turn the screw, so it was a surprise when Chievo took the lead in the 28th minute.
Gianluigi Buffon made a hash of a short pass out to his defence and Gennardo Sardo gratefully swept up the ball to give it to Thereau, who confidently whipped home on the half-volley.
The Bianconeri would not suffer any further embarrassment before the break but they failed to make the most of several chances to equalise.
Quagliarella's snapshot fell to Andrea Pirlo, whose follow-up effort went out for a corner and, two minutes before half-time, Llorente fluffed an easy header from a Mauricio Isla cross.
Juve put their heads together over the interval and contrived to level the scores two minutes after the restart.
Pogba was heavily involved in supplying Quagliarella for two shots against the flailing Puggioni.
The Chievo goalkeeper moved quickly to save both, but could not keep a third out.
Ten minutes later Chievo would find themselves behind when they could have been leading 2-1.
Another mistake from Buffon when dealing with Simone Bentivoglio's shot saw Paloschi bundle over the line, but the offside flag denied him a goal.
Chievo did not protest too much but they were enraged when Bernardini contrived to stub the ball past his own keeper under pressure from Llorente in the 65th minute.
Conte knew his side had been poor and, in his search for a decisive third goal, he introduced the rested Tevez for the final throes.
The Argentinian certainly spiced up the forward line but three minutes of stoppage time were not enough for the former Manchester City man to put his team out of sight in Verona.