Belarusian tennis player Aryna Sabalenka has apologised for allegedly swearing during her WTA Finals match against Ukraine's Elina Svitolina on Friday. "My comment wasn't directed at Elina. I was frustrated with a small group of spectators who were aggressively cheering my mistakes, and I reacted emotionally in the moment," she wrote on Instagram. Sabalenka lost the match 3-6, 6-3, 1-6.