Ashleigh Barty let her frustration show in her second-round Madrid Open match against Tamara Zidanšek, despite coming through the clash to win in three sets.

The Australian appeared to be struggling after losing the second set 6-1 but fought back to win the decider 6-3.

The world number one took issue with a challenge from her opponent, though, as Zidanšek questioned a net service that was called in but then was subsequently overruled.

Despite winning the point eventually, Barty expressed her feelings to the umpire, stating: “You know the system is as much bull**** as I do, don’t you.”

Little more came of the outburst as the Aussie went on to wrap up the match shortly after. Following the match, Barty admitted it had been a challenging day for her.

“It was a very tough match,” she stressed. “I know Tamara has played a lot through qualifying and was very comfortable on clay. It was important for me to serve well and towards the end, I found a little bit more but it was a very tough day.”

Barty will now meet Iga Świątek in the next round after the Polish teenager beat the German Laura Siegemund in straight sets.

Świątek won the 2020 French Open, while Barty won the tournament the previous year. This will be the first meeting between the pair, however, with both having shown impressive form on clay.

Elsewhere, Barty’s rival and Świątek’s good friend Naomi Osaka suffered a shock loss to Karolína Muchová.

Osaka has tended to struggle on clay during her career and her wait for a first career title on this surface continues.