Challenged, became greatly upset (4,2)

I believe the answer is:

took on

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

'challenged' is the definition.
(I've seen this in another clue)

I don't understand the rest of the clue.

(Other definitions for took on that I've seen before include "challenged" , "Got upset < , did recruit" , "Employed" .)

I've seen this clue in The Telegraph.

Want a hint initially instead of a full solution? Install my app