Tennis player Alexander Zverev has cited a malfunctioning glucose sensor as a contributing factor to his semi-final loss at the Halle Open against Taylor Fritz. Zverev explained the device displayed inaccurately high glucose readings despite his actual levels being low. Believing his glucose was elevated, he administered an excessive dose of insulin. This resulted in impaired performance during the match, impacting his energy and focus. Zverev did not disclose specific details about his diabetes management beyond the sensor issue. The incident raises questions about the reliability of continuous glucose monitoring technology in high-pressure athletic situations. He is currently evaluating alternative monitoring options.