Banner to put up with a red dragon, initially (8)
I believe the answer is:
standard
'banner' is the definition.
(I've seen this before)
'put up with a red dragon initially' is the wordplay.
'put up with' becomes 'stand' ('stand' can be a synonym of 'put up with'**).
'initially' indicates taking the first letters.
The initial letters of 'red dragon' is 'rd'.
'stand'+'a'+'rd'='STANDARD'
'to' is the link.
(Other definitions for standard that I've seen before include "Military flag" , "Big tree specially trained" , "kind of lamp" , "Flying colours" , "Against which to measure the rest" .)