Nicolas Gonzalez's thunderous long-range strike beat 'keeper Stefano Turati on 11 minutes, with Kolo Muani giving Juventus a two-goal cushion from a counterattack.
The contest took a twist when Kenan Yildiz was sent off on the verge of half-time for elbowing Alessandro Bianco in an off-the-ball incident, which was checked by VAR.
Juve had to dig deep in the second half, with rock bottom Monza outmanoeuvring the hosts and dictating play. The Bianconeri managed to fend off the threats to scoop maximum points and confirm Monza's relegation to Serie B.
Old Juve player ratings
Michele Di Gregorio — 7
Stroll in the park against his former club. Hardly put to the sword, and ably dealt with any scoring threats.
Pierre Kalulu — 8 (Old Juve man of the match)
Composed display, and brilliantly snuffed out any danger from lively looking Gianluca Caprari.
Renato Veiga — 7
Confident display with impressive aerial ability, which included blocking a Caprari thunderbolt with his head.
Lloyd Kelly — 4
Edgy performance, and was persistently given the runaround by striker Dany Mota.
Weston McKennie — 6
Industrious as ever. Kicked off on the right wing, but played the second half in the middle where he was constantly tested.
Manuel Locatelli — 7
The skipper led by example with a calm and collected display, helping out in defense when Monza poured forward.
Khephren Thuram — 7
A strong opening half, and set up the second goal to put Juve in cruise control. After picking up an injury was replaced, and was missed.
Andrea Cambiaso — 5
Following an ankle injury he looked a shadow of his former self, and made little impact after the interval.
Nicolas Gonzalez — 7
Spectacular long-range strike against the run of play. Was guilty of fluffing his second easy scoring opportunity.
Kenan Yildiz — 5
Was starting to dazzle, and set the ball rolling for the second goal. Lost his cool on the stroke of the half-time whistle to let the side down.
Kolo Muani — 7
First start under Igor Tudor and he initially lacked sharpness. Made up for some early poor finishing with a clinical goal and creative passes.
Juventus subs
Nicolo Savona — 6
Was solid at the back, required to persistently snuff out threats from Monza’s left wing.
Timothy Weah — 5
Utilized to strengthen the backline as Juve were under the cosh following Yildiz’s undignified exit, but he was rarely involved.
Alberto Costa — 5
Late appearance, and hardly got into the game that was already petering out with tactical time-wasting by the hosts.
Juventus: Di Gregorio; Kalulu, Veiga, Kelly; McKennie, Locatelli, Thuram (58, Savona), Cambiaso (57, Weah); Gonzalez (74, Alberto Costa), Yildiz; Muani. Subs: Perin, Conceicao, Adzic, Pinsoglio, Luiz, Rouhi, Mbangula.