Sauce engaging foremost of university tutors, leading those people to make the grade (3,3,7)
I believe the answer is:
cut the mustard
'make the grade' is the definition.
(thesaurus)
'sauce engaging foremost of university tutors leading those people' is the wordplay.
'sauce' becomes 'custard' (I've seen this before**).
'engaging' is an insertion indicator.
'foremost of' says to take the initial letters.
'leading' means one lot of letters go next to another.
'those people' becomes 'them' (I've seen this before).
The first letters of 'university tutors' is 'ut'.
'ut'+'them'='utthem'
'custard' placed around 'utthem' is 'CUT THE MUSTARD'.
'to' is the link.
(Other definitions for cut the mustard that I've seen before include "Harvested brassica plant" , "come up to expectations" , "should prove acceptable" , "impress" , "Reach a required standard" .)