Is just as fast as and plugs away at (5,2)

I believe the answer is:

keeps up

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'is' is the definition.
The answer and definition can be both to do with ownership as well as being verbs in their -s form.
Maybe there's an association between them I don't understand?

I don't understand how the remainder of the clue works.

Can you help me to learn more?

I've seen this clue in the Evening Standard.

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