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.
Manchester United injury list
Manchester United injury list
1/5 Wayne Rooney
There is uncertainty over the extent of the Manchester United captain's injury, with fears he may have suffered ligament damage to his knee during the 3-0 defeat to Everton. Unlikely to feature against West Brom and could miss the rest of the season.
2/5 Michael Carrick
Having limped off in the 4-2 derby victory over Manchester City, it's uncertain if the England midfielder will fit for this weekend. Was unable to even make the bench for the defeat to Everton.
The right-back's return to action has suffered a set-back. After making a short appearance in the 3-0 win over Tottenham in March, the Brazilian has been pushing for full fitness. However he suffered a blow to the ribs in an Under-21 match against Leicester and could miss the rest of the season.
4/5 Marcos Rojo
Having missed the games against Chelsea and Everton due to a groin injury, the Argentina international is pushing for a return and could feature this weekend.
5/5 Phil Jones
Fellow defender Phil Jones also missed the defeats to Chelsea and Evertton but the England international has returned to training after a foot complaint and could play at against West Brom.
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."Reuse content