Shaw, alongside defender Chris Smalling, made themselves unavailable for Manchester United’s clash with Swansea two weekends ago due to fitness concerns, thereby forcing Mourinho to field a weakened backline.
The pair subsequently came under fire by the United boss for their lack of commitment and unwillingness to play through the pain barrier.
But after expressing concerns that he may not feature in United’s long-term plans, Shaw has sought to hit back against Mourinho’s public outburst and prove a point to the volatile Portuguese.
With England in action against Scotland, the youngster spent his weekend hard at work on his fitness.
Shaw took to Twitter to share a short video of himself undergoing a variety of fitness drills, from weighted lunges to resistance-based exercises.
Posting to his 1.36million followers, Shaw captioned the video: “Ticking over on my weekend off.”
The former Southampton player has so far struggled to make an impact at Old Trafford after joining the club for £30m deal two years ago.
Shaw was left sidelined for seven months after breaking his leg against PSV in September 2015 and since then his career at United has faltered.
But after missing out against Swansea, the youngster came through a practice match in front of Mourinho last Friday against the club's Under-23s side at the Carrington training ground.
United return to Premier League action against rivals Arsenal on Saturday, November 19, and Shaw will have his sights firmly fixed on playing some sort of role in the crunch-match fixture.