What does it mean to "keep one's eyes on the ball"?

Native speaker’s answer
Rebecca
To "keep one's eyes on the ball" means to "focus" and give attention to something important. Ex: To get an A on this test, I have to keep my eyes on the ball. Ex: Keep your eye on the ball! We have to win this game! Ex: Tim couldn't keep his eye on the ball and quit university halfway through the year.