The Italy midfielder drove home with just over five minutes remaining to secure three points and ensure that the Bianconeri remain top of Serie A
The Bianconeri took the lead 14 minutes in courtesy of a free kick from Andrea Pirlo, who struck the bar with another sublime set-piece later in the half. However, the two sides went in level at the interval, with Emanuel Calaio heading home just before the half-time whistle.
Juventus bossed the second period but it seemed that their efforts would prove in vain. However, with just five minutes remaining, Marchisio came to their rescue to steal a win that keeps Antonio Conte's men top of the table.
Juve had gone into the game on the back of a fortuitous draw at home to Champions League rivals Shakhtar Donetsk and the defensive frailty that was on show in Turin on Tuesday night was in evidence again at the Artemio Franchi.
Indeed, Siena should have been ahead inside two minutes, but Alessandro Rosina, who was a constant thorn in Juve’s side during the first-half, miscued his first-time strike, after being picked out by Angelo’s pull-back, and the ball ended up bouncing harmlessly into the arms of Gianluigi Buffon.
While the visitors looked vulnerable at the back, Sebastian Giovinco and Mirko Vucinic were causing problems every time they picked up possession at the other end of the field and it was no surprise that the pair played a key role in the Bianconeri’s opener.
Vucinic left two Siena defenders trailing in his wake with a wonderful turn in midfield before slipping the ball wide to Giovinco, who ended up on the deck after bamboozling Felipe with his quick feet. Pirlo took the subsequent free kick and found the bottom corner by ingeniously firing the ball low underneath the feet of the players in the defensive wall, who had collectively jumped in an attempt to make the playmaker’s task more difficult.
The goal unsurprisingly settled Juve and they could count themselves unfortunate not to have doubled their lead before the break, with Pirlo crashing another set-piece against the cross bar on 40 minutes before Claudio Marchisio drew a flying save out of Gianluca Pegolo moments later.
However, Catania continued to threaten at the other end and Calaio squandered a gilt-edged opportunity to level matters midway through the opening period when he fired wide with the goal at his mercy, after being the recipient of a deft lay-off from Ze Eduardo. The veteran striker made amends, though, right on half-time, powering home a header at the far post after Angelo had beaten Paolo De Ceglie to the byline before whipping over the most inviting of crosses.
Juve responded to that setback by replacing De Ceglie during the interval and they looked more defensively sound for the majority of the second-half. In saying that, Rosina had a tremendous chance to edge Siena in front with just over 10 minutes remaining, but he inexplicably failed to get his head on the end of Cristiano Del Grosso's cross.
In the end it was Juve who struck late, and deservedly so, with Pegolo having produced a succession of terrific saves to keep out Juventus, and Giovinco and Arturo Vidal in particular, while Vucinic had seen a measured strike from the edge of the area drift just wide of the post.
Again Giovinco was key, the former Parma man jinking past a couple of players before crossing into the area. The ball was nodded back across the box by Giorgio Chiellini and Marchisio arrived right on cue to drive the ball through a crowd of players and past Pegolo, thus securing Juve their sixth win from seven outings this season.