The Old Lady generally had the better of proceeding and won a huge number of corners, but they fell behind just before halftime as Courtney Meppen-Walter headed City into the lead.
Juve continued to control the match after the break and eventually got the equaliser in the final few minutes when Rugani headed in from close range after a shot came back off the crossbar.
The early stages saw both teams just looking to cope with the dreadful conditions in Italy, as mass surface water severely impacting on players’ ability to keep the ball under control.
Due to the weather, quality was at a premium as a Hordur Magnusson back pass caused Constantin Branescu to panic in goal for Juventus, while at the other end the Italians were creating openings.
Stefano Beltrame tried his luck from a narrow angle, forcing Ian Lawlor into a good save, then moments later Stefano Padovan was played through on goal, but the City custodian prevented a goal again.
City were struggling to create chances, but Jules Ntcham did try his luck on the edge of the area, only for Branescu to pluck it out of the air with relative ease, however he was beaten eventually.
With three minutes left of the first half a corner was whipped into the area where Meppen-Walter rose above Magnusson to nod into the bottom of the goal.
The second half very much followed a similar pattern to the first, with Juventus looking the more dangerous side in attack, while neither team could keep possession due to the amount of water on the pitch.
Federico Mattiello had the first chance of the second period. The ball dropped kindly to him after a melee around the penalty spot, but George Evans threw himself in front of the shot, conceding a corner.
The hosts were convinced they should have been given a penalty ten minutes into the second half when Padovan was blatantly pushed over by Karim Rekik only for the striker to be booked, but they did get a spot-kick three minutes later.
A Juventus corner was sent in to the near post where Kieran Kennedy inexplicably punched the ball, but Lawlor parried away Padovan’s kick to keep City in the lead.
City spent most of the final 15 minutes defending a Juve on-slaught and although the Italians were struggling to break down their visitors, they finally levelled the scores after a flurry of corners.
One of the corners fell to Beltrame on the edge of the area and he hammered a shot against the crossbar, but Rugani was on hand to head in the rebound with six minutes left, and the score remained the same until the final whistle.