The hosts looked like they meant business, taking the lead inside three minutes as a familiar pair combined to devastating effect.
Weston McKennie provided the cross for Vlahovic’s headed winner in December’s reverse fixture, and after smartly bringing down Federico Gatti’s long pass here, he squared for Vlahovic to tuck home, although the shot took a slight nick off Frosinone defender Pol Lirola on its way in.
However, despite possessing the worst away league record this season heading into this weekend, the underdogs stunningly drew level on 14 minutes as Nadir Zortea beat Manuel Locatelli on his outside and produced an inviting cross which was attacked with relish by the head of Walid Cheddira.
Zortea and Cheddira were among five players returning to manager Eusebio Di Francesco’s starting line-up following the dispiriting 3-0 loss to Roma, with another of those, Abdou Harroui, then finding Marco Brescianini with a superb through-ball as the midfielder took a couple of touches under pressure before sensationally firing into the roof of the net.
Home captain Adrien Rabiot was subsequently brought off injured on his 200th Juve appearance, with Southampton loanee Carlos Alcaraz taking his place.
Soon the Old Lady were level though, as Vlahovic was thwarted by Michele Cerofolini seconds before McKennie again fed the Serbia international, who made no mistake with an unerring close-range strike.
Undeterred, Frosinone could have gone back in front when another Brescianini effort whistled over shortly before HT, but after the break, Juve had two golden opportunities as Vlahovic's point-blank header went wide and Daniele Rugani’s menacing shot hit teammate Alcaraz.
Just after the hour, Massimiliano Allegri looked to turn the screw, bringing on teenager Kenan Yıldız and McKennie’s compatriot Timothy Weah, but despite Allegri’s men keeping the pressure on, they failed to regularly test Cerofolini, as Yıldız miskicked at a crucial moment.
With less than 20 minutes remaining, Juventus loanees Kaio Jorge and Enzo Barrenecha entered the fray, shortly before Gatti, against his old club, wasn’t able to quite get his bearings right as the contest entered its final stages.
However, at the death, Vlahovic’s glancing header across goal from a corner was converted at the back post by the unlikely figure of Rugani to deafening roars.
Second-placed Juve are still unbeaten in this H2H (W8, D1) and are now six points behind Inter Milan, who do still have two games in hand on them. Meanwhile, Frosinone remain just three points clear of the relegation zone and welcome 14th-placed US Lecce to Stadio Benito Stirpe next Sunday.
Flashscore Man of the Match: Marco Brescianini (Frosinone)
