United explained after sacking boss Ole Gunnar Solskjaer that they were targeting a coach for six months before hiring a permanent successor in the summer and that has transpired with Rangnick closing in.
News of his imminent appointment was warmly received on social media with fans describing it as 'immense' and the start of a 'new era'.
'We've acquired one of the best footballing brains in the business in Ralf Rangnick, this is huge,' one fan-page wrote.
'Not only will he take charge for the next 6 months, he'll then move up into an alternative capacity role, similar to that of a director. A step in the right direction.'
Andrew Marshallsay added: 'Ralf Rangnick as Man United manager is a massive move.
'He's one of the reasons why football tactics are the way they are these days. He's a tactical genius.'
Manchester United have reached an agreement to name Ralf Rangnick as interim manager
Fans have been left delighted to be on the cusp of appointing a 'tactical genius' like Rangnick
Rangnick, who was nicknamed the 'Professor' during his early managerial career in Germany, has established a reputation as one of the finest footballing brains in the sport.
Liverpool boss Jurgen Klopp and Chelsea manager Thomas Tuchel are among the disciples for his 'heavy metal, rock and roll' football. Bayern Munich boss Julian Nagelsmann also worked closely with Rangnick at RB Leipzig.
United had lost a playing style and identity under Solskjaer, which ended in a humiliating 4-1 loss to Watford, and fans are thrilled at the prospect of better football.
'Ralf Rangnick has a great reputation to build teams from the core,' one fan wrote.
'He's a hard working press offensive manager. Manchester United team will be very exciting & sight to behold. We shall rise above the ashes into the limelight. A new era has begun. We ain't here to take part.'
Another overjoyed fan added: 'He is a master of improving people - not just