After criticism on social media, world number 25 Dayana Yastremska apologised for images of herself in blackface.
Novak Djokovic believes there is an agenda behind the criticism he has faced in the wake of the ill-fated Adria Tour event.
World number 81 Frances Tiafoe announced he had contracted COVID-19 on Saturday, having played in Friday's opening session.
Boris Becker and Nick Kyrgios were involved in a tense Twitter stand-off over the Australian's criticism of Alexander Zverev.
Australian Open champion Sofia Kenin was in decent form in Charleston amid the coronavirus pandemic.
A day on from beating Andy Murray, Dan Evans was the last man standing in the Battle of the Brits.
The third-place play-off at Roehampton will not feature Andy Murray after a shin injury led him to withdraw.
With the ATP Tour set to restart in August, Andy Murray questioned whether the schedule was safe.
Neither the Davis Cup nor the Fed Cup will take place this year after postponements until 2021 were announced.