The Swiss maestro loosens up with a looser serve technique at the Aorangi Park practice courts.
Fabio Fognini knocked off a fabulous 'tweener during his five-set win over Federico Delbonis on Day 4.
World No. 2 has not dropped a set through two rounds.
"I have no problem where I play. I'll play on the practice courts if I need to," says Venus, who played on Court 18 today.
Viktor Troicki lets an umpire have it after a tough loss on Day 4
The Big Four will be serving double duty in Rio.
"I think us, as a country, we have sort of turned the corner," American No. 1 said.