turn ... on its head

[sonyet]

Hi everybody!
What does the following sentence mean?
*The new players turned the old guard of tennis on its head*
Thanks in advance for your help.
S

 

[emsr2d2]

Hi everybody!
What does the following sentence mean?
*The new players turned the old guard of tennis on its head*
Thanks in advance for your help.
S

It basically means to change something completely (literally to turn it upside down). In this context, the new players have completely changed how tennis is played.