The substitute's last-gasp winner broke the visitors' hearts after a superb defensive display had frustrated Antonio Conte's team for much of the match.
The substitute winger, who was booked for diving in the last minute of normal time, redeemed himself when he slotted home from close range after Catania goalkeeper Mariano Andujar flapped at Paul Pogba's searching cross. The goal, coupled with Napoli's surprise defeat to Chievo, mean Antonio Conte's side is now the clear favorite for another Serie A title with 10 games remaining in the season.
The league leaders looked to impose themselves on the game early, but only had an Andrea Barzagli long range effort to show for their endeavors, with the defender's strike flying over the bar.
Mirko Vucinic was rested for the Champions League win over Celtic in midweek, and the break seemed to have done him good as he tested Andujar for the first time, but the goalkeeper turned his shot from distance behind for a corner.
The visitors had decided to try and counter the attacking threat of Conte's side, but they almost took the lead themselves when Alejandro Gomez tried his luck from distance. Gianluigi Buffon was equal to it, though, despite initially spilling his effort.
Long-range efforts then became a theme of the match, with Francesco Lodi and Leonardo Bonucci both firing wide before the home side twice went agonisingly close to breaking the deadlock.
Claudio Marchisio curled a shot wide after good interplay with Vucinic, before the Montenegro striker hit the post after capitalizing on a breakdown in communication in the Catania defense.
The remainder of the half passed with little incident on the field, though Catania coach Rolando Maran was sent to the stands after arguing with the officials.
The second half continued where the first had left off, with Juventus pressing at every opportunity, and Andujar had to be at his best to deny both Bonucci and Paul Pogba in quick succession. Pogba slowly made his way into the match after a quiet start, and he went close again as he volleyed an effort wide from 25 yards.
Vucinic was still the biggest threat for Conte's side, but his finishing wasn't up to its usual standard, highlighted when he could only shoot wide from close range under pressure from the impressive Andujar.
Juventus rang the changes in search of a breakthrough, and one of the substitutes, Alessandro Matri, went close with a header as the game entered its final 10 minutes.
Giaccherini then took center to emerge as the hero, and Fabio Quagriella almost doubled the lead, but Andujar parried well from the Italy striker to keep the scoreline at 1-0.