The most common and most likely answer to this crossword clue is the 10 letter word COELACANTH
I've seen this crossword clue in The Times
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More clues leading to the result COELACANTH
Buddy explains!
The straight part
We know that "Upset all odds and catch one" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case upset all odds and catch one = coelacanth.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does COELACANTH mean?
COELACANTH noun- Either of two species of deep-water fish, Latimeria chalumnae of the Indian Ocean and Latimeria menadoensis of Indonesia.
- Any lobe-finned fish in the order Coelacanthiformes, thought until 1938 to have been extinct for 70 million years.