Tapping into the Chilean forward's skills on the piano, they got the 29-year-old to play a rendition of "Glory, Glory Man United" as he pulled on the famous no.7 kit that is so iconic at Old Trafford.
Nonetheless, it was an effort befitting of the occasion, and one which follows in a long line of over-the-top transfer announcements.
The video was accompanied by the words: "Ladies and gentlemen, please take your seats".
The Steelmen's video shows the burly central defender playing a miniature keyboard - which he later smashes - before walking out on the Fir Park pitch in the pouring rain.
Hartley, who has played for Sunderland, Chesterfield, Hartlepool United, Stevenage and Plymouth Argyle, joined Blackpool from Bristol Rovers in June, signing a two-year contract. Introducing #Pete6 #SIWY #MFC.
Are they doing it right?
United confirmed the arrival of Sanchez from Arsenal on Monday - in a deal that saw him become the Premier League's highest paid player - and accompanied his arrival with a video, which Motherwell have brilliantly recreated.
"I've been at this club for six months and it's a fantastic dressing room, probably one of the best I've been in".
He sealed a loan move to Motherwell on deadline day and has since made 17 appearances north of the border.