The north London rivals meet for the first time this season on Sunday – though both have a Europa League clash on Thursday night to traverse first – with Spurs top of the table and Arsenal struggling in 14th place.
Despite the Gunners’ relatively mixed start to the campaign, Dier was full of praise for the work Arteta has done.
‘I think he’s maybe the most – personally, obviously I’m not on the inside! – but from what I see, the most exciting young manager in Europe, for sure,’ Dier told Sky Sports.
‘I like his way and the way in which he seems to be as a manager so I think they’re in good hands in that sense.’
But Mourinho was not quite so quick to praise his counterpart and does not believe it is possible to single out just one outstanding young manager ahead of others.
When Dier’s comments were put to him, Mourinho replied: ‘I don’t want to go in that direction.
‘He won already an important competition in the first few months of his career, that we cannot deny.
‘And to be the Arsenal coach, you have to be good. If you are not good, you are not there.
‘So yes I think Mikel is a good coach, but I want to respect the others.
‘Especially the others that I don’t know well. And probably they are also very, very talented.’