The fact Burton view the early weeks of the league season as more important than a trip to Old Trafford highlights the issues with a competition that even last season's triumphant manager Mourinho believes could be dispensable.
Shaw made his first appearance of the season in Wednesday's Carabao Cup win over Burton, coming on as a half-time substitution for Juan Mata.
His improvement and content demeanour has not gone unnoticed either, with Mourinho saluting his attitude.
"What I see? In a word; happiness".
"He is a happy guy".
"I'm very pleased with his attitude overall". And we're speaking about some of the best players of the Premier League.
The pair have been duelling it out for the left-wing spot following the arrival of centre-forward Romelu Lukaku and Rashford says they are driving each other on. He doesn't play for a long, long time.
"I played Champions League with Ashley Young at right-back, not [Antonio] Valencia".
Frank de Boer paid the price for overseeing defeats in the opening four league games and successor Roy Hodgson failed to break that run in his first game in charge against Southampton last weekend.
In just one year from the appointment to the post of head coach of Manchester United - Jose Mourinho was able to create such a powerful foundation that will certainly bear fruit both now and in the future.
The competition also offers the chance to secure a trophy ahead of the run-in to the end of the season, which is useful if the club are focused on the Premier League title or balancing duties in Europe or the FA Cup as well.
We should, rather than pitting them against each other, express delight at the risky dynamic on the left hand side now at Mourinho's disposal. We have less points but I think it was a good season last season for many things.
Pep Guardiola made nine changes to his first team squad and included players such as Ilkay Gundogan who hadn't featured in a match for nearly 11 months.
In further good fitness news, club captain Vincent Kompany is back in full training and could even feature against Palace. I think the team collectively enjoyed the game, we look happy at the moment, that's what I want.