Top-seeded Alex de Minaur was forced out of the Adelaide International Monday with an abdominal strain.
The 20-year-old Australian took over as the No. 1 after the withdrawal over the weekend of Novak Djokovic.
"Obviously I'm not in the happiest mood but it's something that happens. I aggravated a bit of an ab injury," De Minaur said. “I've just got to do whatever I can to make sure my body recovers.”
He said his “sole focus” was to make sure he was ready for the Australian Open. The first Grand Slam of the season opens next week in Melbourne.
De Minaur had been playing well heading into the Adelaide International, winning two singles for Australia at the ATP Cup tournament last week and taking Rafael Nadal to three sets.
De Minaur will be seeded No. 20 at the Australian Open after the withdrawal of Japan's Kei Nishikori.
