an uphill battle
A task that is very daunting from the outset and continues to be challenging. The incumbent is so popular that defeating her will be an uphill battle. I'm terrible at math, so I have a real uphill battle ahead of me if I want to improve my grade in Algebra.
uphill battle
and uphill struggleFig. a hard struggle. Convincing the senator to see our point of view was an uphill battle, but we finally succeeded.
an uphill ˈstruggle/ˈbattle/ˈtask
something that is difficult and takes a lot of effort over a long period of time: After the recent scandal, he faces an uphill struggle to win back public support before the next election.