Louis van Gaal will come face to face with his friend Jose Mourinho on Sunday in the biggest test of his Old Trafford reign to date.
With so much focus on Van Gaal's relationship with his former assistant, one sub-plot has flown under the radar in the build-up to the match - that of Shaw's relationship with Chelsea.
Shaw spent much of his childhood on the terraces at Stamford Bridge, and he actually had a trial at the west London club as a youngster, but he was rejected after being deemed too short.
The Blues had a chance to sign Shaw again this summer, but they balked at his wage demands, according to Mourinho, and United swooped to land the Londoner.
"Playing against Chelsea is a big thing in my family and among my friends because I was born around that area of London," Shaw told Inside United.
"I used to watch them when I was younger."
Almost all of Shaw's family, including father Paul - who is expected to be at Old Trafford on Sunday - are Blues, which made for split loyalties in the Shaw household when the teenager turned out for Southampton at Stamford Bridge last year for the first time.
Shaw admits that match, in which he set up Jason Puncheon for the equaliser in the 2-2 draw, is small fry when compared to the colossal battle which is set to unfold at Old Trafford on Sunday.
"When I first played at Stamford Bridge with Southampton it was a bit of a surreal experience in a lot of ways because it was at a ground I'd visited as a kid," Shaw added.
"But playing against Chelsea with United at Old Trafford is a different proposition altogether.
"I'm really looking forward to it, especially with how big this fixture is.
"Everyone knows that United-Chelsea games are massive
It's one of the biggest games in world football and there will be people everywhere watching it on TV."
Many people have been keeping a keen eye on Shaw's progress too since he joined United for almost the same fee they paid to sign Wayne Rooney a decade ago.
The defender was criticised by Van Gaal for turning up to pre-season training out of shape, but he soon earned a place in the manager's good books for the way he regained his fitness.
On the pitch, Shaw admitted earlier this week that his performances have not been up to scratch since his move
"The fans haven't seen the best of me yet
I know I haven't been up to my full potential," he said.
This weekend's game therefore provides the England international with a perfect opportunity to show he is up to the task of being a Manchester United regular.
"There aren't many games that are bigger than this one and that's why I'm really hoping to be a part of it
I want to show people what I can do in games like this," he said.
Chelsea are favourites for Sunday's clash for a reason.
The unbeaten Blues have dropped just two points so far this season and lead the Barclays Premier League by five points.
United sit 10 points behind Mourinho's men because of their inconsistent form.
Van Gaal, who is three months into his tenure, thinks his team will improve if, like Mourinho, he is given time.
"Jose has worked more than one year already with his team and last year they didn't win any prize, so you have to build up and he has built up Chelsea," said the United boss, who watched his team draw 2-2 at West Brom on Monday.
"They are playing like a team and I want my team to do that as well, but to play for 90 minutes.
"We did that against West Bromwich Albion, played as a team, but we also made individual errors
That was our problem."
Mourinho takes his Chelsea side to Old Trafford on Sunday shunning the conservative approach to instead chase a victory over Manchester United and an extension to the Premier League leaders' unbeaten start to the season
Mourinho will play against one-time mentor Louis van Gaal for the second time in competitive matches, bidding to build on the Blues' seven wins in eight Premier League matches so far this season.
Last season, just three games into his second spell as Chelsea boss, Mourinho opted against fielding a recognised striker at Old Trafford.
This time Chelsea travel with a win on their minds.
"Try (for) the best result as always," Mourinho said.
"Try to play as good as we are playing and we are always trying to play, respecting an opponent that is one of the best and most difficult in the Premier League.
"We are confident, we are in a good moment, in a good situation and there is no reason for us to change our feeling.
"We play against a big team, yes, we know that, but we feel ourselves in a very good moment."
Mourinho is prepared to risk the fitness of striker Diego Costa, who has scored nine goals in seven Premier League games and is recovering from a hamstring problem and viral infection.
Loic Remy (groin) is out, while midfielders John Obi Mikel (foot) and Ramires (groin) could return alongside forward Andre Schurrle (illness).
Thibaut Courtois is to return in goal after Petr Cech started Tuesday night's match against Maribor and Filipe Luis is likely to play at left-back with Cesar Azpilicueta suspended.
Cesc Fabregas, who was linked with United in recent seasons, has been key to Chelsea's form this term since signing from Barcelona.
But Mourinho is confident his side can adapt if United try to shut down the Spain playmaker, just as Crystal Palace tried last weekend.
The Blues boss added: "If he doesn't run (the game), somebody runs it
Against Crystal Palace he had individual police and we played without him in the first half when he had that individual policing.
"We are very confident about ourselves
I'm not interested in thinking which team Man United play, who is playing, who is not playing
I'm not interested.
"We are playing well, we are confident, we are top of the league, we are in a good position.
"The camp is happy and we are ready for the game."
Source : PA
Source: PA