My company rallied at first (3)
I believe the answer is:
cor
'my' is the definition.
(both are expressions of surprise)
'company rallied at first' is the wordplay.
'company' becomes 'co' (abbreviation).
'at first' indicates taking the first letters.
The first letter of 'rallied' is 'r'.
'co'+'r'='COR'
(Other definitions for cor that I've seen before include "Blimey" , "Gosh" , "Surprised expression" , "Expression of surprise" .)