Side with expert featured in business paper (5)
I believe the answer is:
facet
'side' is the definition.
(I've seen this before)
'expert featured in business paper' is the wordplay.
'expert' becomes 'ace' (ace can informally mean very good).
'featured in' is an insertion indicator.
'business paper' becomes 'ft' (Financial Times newspaper).
'ace' inserted inside 'ft' is 'FACET'.
'with' is the link.
(Other definitions for facet that I've seen before include "Small flat surface of cut gemstone" , "view" , "side of rock" , "Gem's cut side" , "Flat surface on a cut gem" .)