The American cruised to a 6-1, 6-1 victory as the final tennis Grand Slam of the year began on the hard courts of Flushing Meadows in New York City.

This was the most eye-catching opening round match in the women's draw as it pitted home star Williams – a 23-time Grand Slam champion – against her Russian rival who has herself won five Grand Slams.

Williams, the eighth seed who is hoping to win a seventh US Open, was ruthless and did not allow Sharapova, the 2006 winner at Flushing Meadows, to get going.

She won twice as many points as the Russian and converted on five out of six break point opportunities.

Thirty-seven-year-old Williams, who has now beaten Sharapova in 19 consecutive matches, said: "It's an incredibly tough draw.

"She is such a good player, when you play her you have to be super focused."

Sharapova will now drop out of the world's 100.

Williams remains on course to reach a second consecutive final, with her defeat last year to Japan's Naomi Osaka overshadowed by her on-court clash with chair umpire Carlos Ramos.

Other women's games on day one saw Australia's second seed Ashleigh Barty, the French Open champion, come from behind to oust Kazakhstan's Zarina Diyas 1-6, 6-3, 6-2.

Third seed Karolína Plíšková of the Czech Republic needed two tie-breaks to beat compatriot Tereza Martincová, who came through the qualifying competition, 7-6, 7-6.

Germany's Angelique Kerber was a casualty as the 2016 winner and three-time Grand Slam champion lost to France's Kristina Mladenovic.

The 14th seed went down 7-5, 0-6, 6-4.

There was home success for Serena's sister Venus Williams, a two-time US Open winner, who brushed aside China's Zheng Saisai 6-1, 6-0.

Tenth seed and 2017 finalist Madison Keys was another home winner as she beat Japan's Misaki Doi 7-5, 6-0.

In men's action, defending champion and top seed Novak Djokovic eased into round two.

The Serbian 16-time Grand Slam champion powered past Spain's Roberto Carballés Baena 6-4, 6-1, 6-4 as he searches for a fourth US Open title in all.

"Getting out of the blocks took a little bit of time, but I was eventually able to capitalise in the big moments," said Djokovic.

Swiss legend Roger Federer, a 20-time Grand Slam champion and the third seed, survived a scare as he dropped the opening set against India's qualifier Sumit Nagal.

Federer, a five-time champion in New York, recovered to win 4-6, 6-1, 6-2, 6-4.

Russia's fifth seed Daniil Medvedev was another winner as he continued his fine run of form.

The Cincinnati Masters champion brushed aside Prajnesh Gunneswaran of India 6-4, 6-1, 6-2.

Italy's 11th-ranked Fabio Fognini was the biggest seed to fall as he was beaten 6-3, 6-4, 6-7, 6-3 by American Reilly Opelka.

Japan's seventh seed Kei Nishikori knocked out Argentinian qualifier Marco Trungelliti, who retired when 6-1, 4-1 down.

First round matches will continue tomorrow.

Osaka will begin her title defence as the women's top seed against Russia's Anna Blinkova, with Spain's three-time winner and 18-time Grand Slam champion Rafael Nadal opening his account as second seed by meeting Australia's John Millman.