“I was really excited when he was given the job. I thought he was a great appointment,” Thornley told Love Sport Radio.
“He's a winner and United needed that. After Sir Alex Ferguson you had David Moyes and Louis van Gaal and neither of those two it worked out for.
“When you hear a name like Jose Mourinho come up, you think 'brilliant, this is what can really make us tick again’.”
Poor results at the start of the campaign were then marred in off-field controversy after Mourinho fell out with Paul Pogba.
Time could be ticking for Mourinho after Sunday's defeat (Image: GETTY)
Former player Ben Thornley thinks the board may have a decision to make (Image: GETTY)
The Frenchman was an unused substitute at Anfield on Sunday.
“Unfortunately, the players he's brought in are not performing - yes we know Lukaku did last year but he hasn't done this year, Sanchez hasn't worked out, Pogba for whatever reason has either fallen out with him or just doesn't fancy him so he's been on the bench for three out of the last four games,” Thornley continued.
“If you're not winning matches, no matter what club you're at, then obviously as a manager your job is going to be at risk at some stage.”
The 43-year-old - who played for the club between 1993 and 1998 - then offered insight into what the board might be thinking in such a difficult time.
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This is United's worst ever points tally at this stage (Image: GETTY)
“I don't know what the hierarchy are thinking but they must be looking at that league table thinking 'if we can't claw some results back in the next four games when we play four games against teams in the lower half then even getting into the top four or five is going to be increasingly difficult’,” he added.
“It's very true, They have got a decision to make, a very tough one, but United need to be in one of those Champions League spots come May and at the moment that doesn't looking like it's going to happen.”
United are now 19 points adrift of Liverpool who are at the top of the table.
Mourinho admitted after the match that the title is no longer a possibility but he remains confident his side can still come in the top four, despite being eleven points behind Arsenal.