Tennis star Iga Swiatek has been booed by spectators after smashing a ball at a ball boy in an ugly act of sportsmanship.

Iga Swiatek was beaten by Mirra Andreeva in the semi-finals of Indian Wells on Friday and she narrowly avoided hitting a ball kid in the third set.

Former world No.1 Iga Swiatek was booed off the court after nearly hitting a ball kid in a moment of anger during her loss to teenager Mirra Andreeva at Indian Wells. Andreeva, 17, became the youngest finalist since 2001 with the stunning 7-6 (7-) 1-6 6-3 win over the defending champion, much to the delight of the crowd.