Get something in one
Definition 1 of 1
Pro Tip 1/3Instant Success
Used when someone achieves something without any prior attempts or failures. 
He swung the bat and got a home run in one.
Pro Tip 2/3Immediate Understanding
Indicates quick comprehension without needing further explanation. 
She explained the theory and I got it in one.
Pro Tip 3/3First Attempt
Emphasizes success or understanding on the first try, often surprising others. 
I guessed the card you were thinking of and got it in one!