Context: Marin Čilić claimed his first grand slam title, defeating Kei Nishikori, also playing in his first major final.\n\nQuestion: who won the men's singles title of the us open tennis grand slam 2014?
Let's be accurate as possible. Think before you answer.
Marin Čilić
The relevant information to answer the above question is: Marin Čilić claimed his first grand slam title, defeating Kei Nishikori, also playing in his first major final.

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The final answer: Marin Čilić