When Anthony Martial posed for a photo with the Carabao Cup trophy he probably didn't think it would cause such a stir on social media.
Martial's season has been typical of his time at Old Trafford: a pre-season of optimism and encouraging performances followed by inconsistent performances, moments of brilliance and long spells on the sidelines.
Martial has been unavailable for 26 of United's 40 games in all competitions this season, meaning he has made just 14 appearances.
The 27-year-old French attacker missed United's 2-0 win against Newcastle in the Carabao Cup final on Sunday with a hip complaint, so had to watch United win a first trophy in six years from the stands.
Still, given that Martial made three appearances during United's run to the final, it was no surprise to see him join in with the post-match celebrations.
What United fans were perhaps not expecting was for the striker to inadvertently reveal United's set-piece routines and tactics.
After the match, Martial posted a photo on Instagram of him posing for a group photo with United's medical staff.
There's an obvious joke to be made there but some eagle-eyed supporters noticed that in the background of the photo, stuck to the dressing room wall, are what appear to be laminated print-outs of United's set-piece routines.
While some fans on Twitter noted that United's set-piece tactics will change game-by-game, others were less than impressed by Martial's carelessness.
@TLF_MUGA said: "We gotta get Tony out of Ten Hags kitchen!"
United's set-piece preparations clearly paid off, as Casemiro opened the scoring when he headed Luke Shaw's wicked free-kick delivery past Loris Karius.
Martial captioned his photo with: "Thanks to the fans the atmosphere was amazing, I can't wait to be back," suggesting that he isn't far off a return to the side.
With United still fighting in the Premier League, Europa League and FA Cup, fans will be hoping he can boost Erik ten Hag's attacking options. Just don't let him in on any top-secret plans.