The 33-year-old appeared to have been overtaken by his emotions, but quickly raised a hand to apologise to the travelling United fans for celebrating the goal against them. Valencia, which earlier beat Young Boys 3-1, is two points further back.
Manchester United boss Jose Mourinho wants to ensure his star man Paul Pogba is not too emotional on his return to Turin. As Cristiano Ronaldo was keen to point out, Juventus should have been three or four up by the time Juan Mata equalised with that sumptuous pressure free-kick.
DF Victor Lindelof, 6 - fearless block from a Ronaldo shot early on but lost him when Leonardo Bonucci floated a ball over the top to allow the former United man to smash Juventus into the lead. I respect Juventus, I respect their players, their manager - I respect everything.
Ashley Young quite clearly eyed it up before making a dummy run.
City has also lost only one match in any competition this season - a 2-1 setback at home against Lyon - and has scored 12 goals in its past two matches.
United's players sprinted towards their manager in delight.
Real Madrid - Champions League - 7 November 2018
Next up for the Argentine coach is a Champions League clash against Viktoria Plzen at the Doosan Arena on Wednesday night. But any hopes Plzen harboured of a shock win were wiped out with two quickfire goals in the 21st and 23rd minutes.
"It´s not that we spoiled his (Ronaldo) goal, but five minutes from the end this shouldn´t have happened basically", said Juventus coach Massimiliano Allegri, whose side fell to their first defeat of the season.
United have endured criticism this season, but have come through their sticky period, with Sunday's showdown ready to provide the ultimate test of where they are as a team, and whether they can get back into the title mix. "It's a great team spirit". City have scored 12 goals in their last two matches and are in unbelievable form, with Riyad Mahrez showing why he was right to leave Leicester and join a bigger club.
Goaded by the home fans throughout, he reacted at the end by surging on to the field and cupping his ear to the home supporters before being led off the field. Although the Portuguese admitted that he probably should not have done that, most United fans were delighted that he did.
Rashford is now in Turin with the Manchester United squad as they prepare to take on Ronaldo's Juventus at the Allianz Stadium in the Champions League on Wednesday evening. "I was happy for the goal but disappointed because we should have won the game easily by three or four goals". In 2015, he was even named the Premier League's best free-kick taker of all time in a poll.
City has only dropped points against Liverpool this season and has lost only one league match at home in almost two years - but that was against United in April. It was one of those nights.