New York - Serena Williams declared herself "ready" for an opening-night showdown with Maria Sharapova as the US Open began Monday with top-seeded defending champion Novak Djokovic set to seize the early spotlight.
Williams, seeking her seventh US Open title, is chasing her 24th Grand Slam singles crown, which would match Margaret Court's all-time record.
The 37-year-old American is 0-3 in Slam finals since becoming a mother two years ago, her last Slam crown coming at the 2017 Australian Open while pregnant.
And while she retired from the WTA Toronto final with back spasms and withdrew from another tuneup in Cincinnati, Williams said she is well prepared for the Flushing Meadows fortnight.
"Ready in NY for the US Open," Williams posted Monday morning on Instagram. "I'm on tonight."
She's facing an emotional rival in 32-year-old Sharapova, who defeated Williams in the 2004 Wimbledon final and the 2004 WTA Tour Championship. Since then, Williams has won 18 matches in a row over the Russian, the most recent in the 2016 Australian Open quarter-finals.
The blockbuster matchup at Arthur Ashe Stadium will mark the first time Williams has played Sharapova at the US Open, which the Russian won in 2006.
Sharapova upset Simona Halep, the reigning Wimbledon champion, in a first-round US Open match two years ago and has reached the fourth round at New York the past two years.
Djokovic, who has won four of the past five Grand Slam singles titles contested, launches his bid to become the first back-to-back US Open champion since Roger Federer won five in a row from 2004-2008.
The Serbian star will meet Spain's Roberto Carballes Baena in an opener on Ashe.
Djokovic owns 16 Grand Slam titles and is chasing the record 20 won by Roger Federer with Spain's Rafael Nadal on 18. Together the "Big Three" have won the past 11 Slam titles and are the heavy favorites to add to that domination at the US Open.
Federer opens his quest for his first US Open title in 11 years and his first Slam crown since last year's Australian Open against India's Sumit Nagal after the Sharapova-Williams showdown.
Reigning French Open champion Ashleigh Barty, the second seed from Australia, and Czech third seed Karolina Pliskova make early starts in their bid to overtake defending women's champion Naomi Osaka for the world number one ranking.
Barty takes on Zarina Diyas of Kazakhstan while Pliskova faces compatriot Tereza Martincova.
Those two, as well as Halep, could dethrone the Japanese star from atop the rankings here. Osaka and Halep must win the title to secure the number one spot, with Pliskova needing at least a quarter-final run and Barty being the front runner based on defending fewer points from last year's Open than Osaka.