Manchester City made a flying start to the Champions League campaign with a 3-0 win against Shakhtar Donetsk.
Manchester United spent USD 66 million on buying Fred from Shakhtar Donetsk in June but he has made just six Premier League starts.
Juventus have maximum points after three games in Group H, and host Mourinho's side in Turin next.
Brazilian international midfielder Fred completed his move to the team he says are the "biggest club in the world" Manchester United for a reported £50 million ($67 million) on Thursday.
Fred caught the eye in Shakhtar's run to the last-16 of the Champions League, where the Ukrainians only lost out on away goals to Roma.
UEFA Champions League: Pep Guardiola made seven changes to his starting XI including handing a competitive debut to 17-year-old midfielder Phil Foden.
Real Madrid suffered a humiliating defeat to Barcelona in La Liga but Rafael Benitez's side will look to bounce back when they travel to Ukraine to face Shakhtar Donetsk.
Sergio Ramos hasn't featured since dislocating his shoulder in last week's 4-0 win over Shakhtar Donetsk and joins Gareth Bale, James Rodriguez and Danilo on the sidelines.
After joining Donetsk from Gremio in January 2010, Douglas Costa scored 38 goals and helped the Ukrainian side collect five league and three cup titles. The 24-year-old was also part of the Brazilian national team at Copa America.
Xabi Alonso picked up his second booking after 65 minutes but Bayern Munich comfortably held on to secure a positive result vs
Shakhtar Donetsk's Brazilian forward Luiz Adriano said that fans taunted him from the stands and were racist in their choice of words used against him.
Bayern Munich humbled AS Roma in their backyard, claiming a stunning 7-1 victory while Jose Mourinho's Chelesa F.C. netted six times in their thumping win over Maribor. Ukranian club Shakhtar also contributed to the goal spree, winning 7-0 against BATE Borisov.
Six players for champions Shakhtar Donetsk and an Argentine with Metalist Kharkiv are too worried for their safety, the reports said.
A 6-3 victory meant that City have now won all eight of their home games this season, scoring 35 goals.
Manchester United are languishing at the ninth spot in the EPL points table after back-to-back losses to Everton and Newcastle United but have been unbeaten in the Champions League so far. A win against Shakhtar will help them qualify as the top team from their group.
Stefan Kiessling scored with his side's first real chance in the 22nd minute, when he rose above his marker to meet Giulio Donati's deep cross. He then claimed his second in the 72nd minute.
United had the better of the early exchanges, Robin van Persie, who was returning to the starting XI for the first time since the opening group win against Bayer Leverkusen, curling a shot high over the bar in the ninth minute after a super ball by Tom Cleverley.
Manchester United was held to a 1-1 draw at Shakhtar Donetsk, while City's former coach Roberto Mancini steered Galatasaray to a 2-2 draw at Juventus, just two days after taking charge of the Turkish side.