Serena Williams out of Italian Open due to Achilles injury

Serena's challenge unsuccessful as Azarenka moves on to US Open final (0:40)

Serena Williams loses the third and final set to Victoria Azarenka, who moves on to face Naomi Osaka in the US Open final. (0:40)

ROME -- Four-time champion Serena Williams withdrew from the upcoming Italian Open, citing the Achilles issue that bothered her in a loss to Victoria Azarenka in the US Open semifinals, organizers at the Foro Italico announced Saturday.

Williams took a medical timeout for a tape job on her Achilles tendon during her three-set loss on Thursday.

"I regretfully must withdraw from the [Italian Open] due to an Achilles strain," Williams said. "I'm so humbled by the continuous support from my fans in Rome and I look forward to making my return soon."

The Italian Open, which was rescheduled from May because of the coronavirus pandemic, begins Monday.

Azarenka remained entered for Rome.

In the men's tournament, US Open finalists Dominic Thiem and Alexander Zverev withdrew, as did Daniil Medvedev, who lost to Thiem in the semifinals in New York.

Nine-time champion Rafael Nadal headlines the field in the Italian capital, marking his return to tennis after a seven-month layoff. The Spaniard has been practicing in Rome for several days.

Top-ranked Novak Djokovic, who was disqualified from the US Open, is also entered.

The clay-court tournament in Rome is a warm-up event for the French Open, which starts Sept. 27.