All-time great Serena Williams has given the thumbs down to compatriot Tennys Sandgren as the unheralded American attempts to reach the semi-finals of the Australian Open.
"Turns channel," the 23-time major winner tweeted as Sandgren took the court in his quarter-final with fellow outsider Hyeon Chung.
The missive is being widely read as a reference to Sandgren's support for the politics of US President Donald Trump.
Williams isn't defending her title at Melbourne Park after the birth of her first child in September.