Juve lead the way in Group H with two wins from two, whereas United are two points further back after drawing with Valencia in their last European outing.
The picture to the right could act as an accurate illustration for a number of things.
How close was Jose Mourinho to being sacked as United boss? How close was he to pulling off a hugely impressive win at the home of his former club on Saturday? How close was he to the end of his tether when Chelsea coach Marco Ianni taunted him after the last-gasp equaliser at Stamford Bridge?
Few could begrudge Mourinho's angry reaction to the unsportsmanship shown by the Chelsea bench - even if he has been guilty of it himself on a number of occasions in his career - as Ross Barkley's 96th-minute equaliser could make a huge difference to United's season.
Seconds away from winning back-to-back matches and climbing up to eighth in the table, United have now instead won just one of their last six outings and sit 10th - already nine points adrift of leaders Manchester City and Liverpool.
One thing that the last two results have shown is that the players are still willing to fight for their manager, though, with stirring second-half comebacks against Newcastle United and then Chelsea either side of the international break.
Of course, giving teams that initial advantage by putting in a poor first-half performance is something United still need to stamp out of their game, but one of the most damning conclusions from previous matches this season was the lack of fight and urgency from the players - a criticism that certainly cannot be levelled at them from the past two outings.
There is still plenty to sort out for Mourinho, though, and the visit of an in-form Juventus side is perhaps something he didn't need considering that his side have kept just three clean sheets in their 13 matches this season.
Two of those clean sheets have come from their two Champions League outings, though, making them one of only four teams yet to concede a goal in this season's competition.
Juventus are another one of those, so United will need a vast improvement from their dour goalless draw against Valencia in their previous home game in the group stages - one of four matches the Red Devils have failed to win from six outings in front of their own fans across all competitions this season.
United have only lost one of their last 22 European matches at Old Trafford, though, a run which stretches back to a 2-1 defeat at the hands of Real Madrid in 2012-13 when Ronaldo scored the winner for Los Blancos.
Recent Champions League form: WD
Recent form (all competitions): DLLDWD
The return of Ronaldo will dominate all of the headlines in the buildup to this match, but it is something which looked in serious doubt at one stage.
The five-time Ballon d'Or winner was shown a straight red card in Juve's Champions League opener against Valencia, but a disciplinary panel limited the suspension to one match, making him available for the double-header against his former club.
Ronaldo has scored a staggering 455 goals in 448 appearances across all competitions since leaving Old Trafford, and while European giants such as United and Real Madrid are floundering post-Ronaldo, Juventus have only gone from strength to strength since his arrival.
Already on an unprecedented run of seven successive Scudettos, Juventus have made their best-ever start to a season this term to quickly establish themselves as the front-runners to lift the title yet again.
Massimiliano Allegri's side did see their 100% start ended on Saturday, though, with Genoa recording an impressive 1-1 draw at the Allianz Stadium to halt what had been a 10-match winning streak across all competitions.
Saturday's result was also the first time Juve had failed to score two or more goals in a game this season, although that record - and their winning form - is still intact in terms of away games ahead of their trip to Old Trafford.
Indeed, Juventus have not been beaten on the road in any competition since November of last year, a run of 22 games which includes 19 wins and victories at the likes of Real Madrid and Tottenham Hotspur in the Champions League.
The Bianconeri are now undefeated in their last five European away games, including wins in each of their last four - most recently beating Valencia 2-0 on matchday one despite the sending-off of Ronaldo after less than half an hour.
Paulo Dybala stepped up in Ronaldo's absence against Young Boys last time out with a hat-trick, but expect the spotlight to be back on the prodigal son on Tuesday night.
Recent Champions League form: WW
Recent form (all competitions): WWWWWD
Anthony Martial is expected to keep his place in the United side after scoring twice against Chelsea to take his tally to three goals in his last two games for the club.
Fellow forward Romelu Lukaku is not in such hot form in front of goal, though, having now failed to find the back of the net in his last seven outings for United.
Lukaku is nonetheless expected to lead the line once again in what could be an unchanged team from the one which came so close to victory at Chelsea.
Juventus will be able to welcome Ronaldo back into the starting lineup, with the Portuguese talisman returning to a club where he scored 118 goals in 292 appearances.
The visitors could be without former Liverpool midfielder Emre Can, who may need surgery for a thyroid problem.
Allegri rested Giorgio Chiellini and Dybala for the weekend draw with Genoa, and both could be in line to return for this match.
Man Utd possible starting lineup:
De Gea; Valencia, Smalling, Lindelof, Shaw; Mata, Matic, Pogba; Sanchez, Lukaku, Martial
Juventus possible starting lineup:
Szczesny; Cancelo, Bonucci, Chiellini, Sandro; Bentancur, Pjanic, Matuidi; Dybala, Mandzukic, Ronaldo
Head To Head
These two clubs met eight times between 1996 and 2003, but this is their first meeting since United ran out 3-0 winners in Turin more than 15 years ago.
The overall record between the two clubs stands evenly at five wins apiece and two draws, with 15 goals scored each too, but United are unbeaten in their last four meetings including perhaps the most famous - their semi-final triumph en route to the treble in 1999.
United have won their last five home games against Italian opposition and are unbeaten in their last eight home and away, but Juve have also not lost in their last eight meetings with Premier League teams including four successive visits to England without defeat.
We say: Man Utd 1-2 Juventus
United have shown signs of improvement in their last two games, but this is a Juventus side in fine form and with the players who could punish any slow start. Juve are among the favourites to lift the trophy this season, and Tuesday could prove to be the first major test of their credentials.