Be, come, etc. within a whisker of something/doing something
Definition 1 of 1
Pro Tip 1/3Closeness
This phrase emphasizes a narrow margin by which something almost happened but didn't. 
She was within a whisker of setting a new record.
Pro Tip 2/3Near Success
It's often used to talk about almost achieving a positive outcome or success. 
He came within a whisker of winning the lottery.
Pro Tip 3/3Tension and Drama
The phrase can be used to create a sense of drama or suspense about the outcome. 
The explorer came within a whisker of finding the lost city.