Australian Open: Alex Michelsen upsets Tsitsipas, thanks his mom

MELBOURNE, Australia — Alex Michelsen produced the biggest win so far of his fledgling career to upset 2023 runner-up Stefanos Tsitsipas in the first round of the Australian Open, and he knew instinctively where credit was due. The 20-year-old American overcame nerves on his serve in the fourth set before clinching a 7-5, 6-3, 2-6,