Learn English – How to describe a person who has done well in every task except one, but he has done extremely bad in that ‘one’ task

phrase-requestssingle-word-requests

I mean, "How to describe a person who has done well in every task except one, but he has done extremely bad in that 'one' task which adversely affects the overall result.
I don't literally mean one though.

For example, someone gets extremely good marks in every subject (except one) in school — he's the top scorer in each individual subject (except one) — but he's got extremely low marks in one of them, and as a result he's no more first.
We can say he is inconsistent. But it's not exactly what the condition is. It doesn't emphasize the extremeness. Bottleneck is another word which I think could be used. But how do we say it — "He made a bottleneck?"

I'd prefer the word/phrase which fills the following blank:
"He is ____."

Best Answer

He has an Achilles heel. This implies that his excellence is crippled by a single, titanic flaw.

Apologies for the wiki-link, but the OED didn't capture the full meaning. Link-Wiki