Bencic has tested positive for COVID-19 after her trip to Abu Dhabi and has "severe symptoms", she said on Tuesday, a day after Rafa Nadal announced he had also tested positive.
Emma Raducanu is the second teenager to make an impact in the women's draw this week as 19-year-old Canadian Leylah Fernandez has also reached the last four.
World number 12 Belinda Bencic dug deep to overpower the Czech Republic's Marketa Vondrousova 7-5 2-6 6-3 on Saturday and win the Tokyo Games women's singles title.