Former Wimbledon champion Elena Rybakina defeated Marta Kostyuk, 6-2, 6-2, to claim her third WTA Tour title of the year at the Porsche Grand Prix in Stuttgart on Sunday. Kazakhstan’s Rybakina broke her Ukrainian opponent in the opening game en route to victory on fourth match point in 1 hour 9 minutes. She won 15 of her points on serve in the first set and saved all three break points against her in the second, while breaking Kustyuk four times overall. World number four Rybakina lifted her eighth career trophy, with her previous titles this year from now five finals coming in Brisbane and Ab…