Pakistan, April 28 -- Elena Rybakina said she has lost faith in the electronic line-calling system after the Australian Open champion was left fuming over a disputed call during her three-set victory over Zheng Qinwen at the Madrid Open on Sunday. The flashpoint came when China's Zheng was awarded an ace for 40-0 while serving at 4-3 in the second set, despite the mark appearing well out.

"Well with this thing, I won't trust it at all," Rybakina told reporters after her 4-6 6-4 6-3 victory sealed a spot in the last 16. "Because there was no mark even close to what the TV showed."

The two-time Grand Slam winner compared the incident to Alexander Zverev's clash with officials at the men's tournament in Madrid last year, when the German wa...