NEW YORK, Sept 2 — Kazakhstani tennis player Yulia Putintseva has apologised for her rudeness to a ball girl at the US Open.

The controversial incident saw the Louis Armstrong Stadium erupt in boos after her bizarre interaction with the ball girl left many baffled.

The 30th seed had grown increasingly frustrated as a third-round showdown with Jasmine Paolini of Italy slipped away from her.