Utmost effort required to come equal top (5,4)

I believe the answer is:

level best

I'm a little stuck... Click here to teach me more about this clue!

'utmost effort' is the definition.
(I've seen this before)

'equal top' is the wordplay.
'equal' becomes 'level'.
'top' becomes 'best' (similar in meaning).
'level'+'best'='LEVEL BEST'

'required to come' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.

Can you help me to learn more?

(Other definitions for level best that I've seen before include "Utmost effort" , "Hardest" , "Maximum efforts" , "joint winners?" .)

I've seen this clue in the Sydney Morning Herald.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.