World number one, Poland’s Iga Swiatek defeated Russia’s Daria Kasatkina in straight sets. With this victory, she made a winning start at the WTA Finals. Swiatek, 21, beat the Russian 6-2 6-3 and recorded her 46th straight-set win this year on the tour. This is the most main draw straight-set wins recorded in a single WTA season since 2013.