Answer
Prior to 2016, Konta achieved her best result at the Australian Open, when she reached the semi-finals in 2015. In that tournament, she defeated No. 7 seed Elina Svitolina in the third round, No. 1 seed Serena Williams in the fourth round, and No. 4 seed Agnieszka Radwanska in the quarter-finals. She then lost to No. 2 seed Maria Sharapova in the semi-finals.