Dic: pit as a verb

• You will be pitted against people who are every bit as good as you are.     
• This was one man pitted against the universe. 
• The rules of the tournament pit their team against ours. 
• John pitted Mary against Sally in the tennis match.

VERB : usu passive | If two opposing things or people are pitted against one another, they are in conflict.

.... Cobuild

cf.

• You won't accomplish anything unless you put your shoulder to the wheel. 
• I put my shoulder to the wheel and finished the job quickly.

have one's shoulder to the wheel; 

keep one's shoulder to the wheel; 

pit one's shoulder to the wheel

Fig. to do the hard work that needs to be done; to focus on getting a job done.

... http://idioms.thefreedictionary.com/pit