Number one in game twice rearranged (6,3)

'twice rearranged' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'number one in game' is the wordplay.
I cannot quite see how this works, but
'number' could be 'm' (M is an example) and 'm' is present in the answer.
'one' could be 'i' (Roman numeral) and 'i' is located in the answer.
an anagram of 'game' is 'gema' which is within the remaining letters.
The remaining letters 'age' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...

Can you help me to learn more?