Serena Williams is arguably the most accomplished player in the history of tennis.

Boasting 23 Grand Slam singles titles, Serena also won a further 14 Grand Slam doubles titles alongside her sister, Venus.

The sisters started playing tennis from a young age in Compton, California, and they blossomed into two of the greatest players the sport has ever witnessed.

Many would consider Serena to be the best WTA player of this century, especially when considering the wealth of accomplishments she has collected.

US player Serena Williams (L) and her sister US player Venus WIlliams (R) pose with their trophies after winning their women's doubles final match against Czech Republic's Andrea Hlavackova and Czech Republic's Lucie Hradecka on day 12 of the 2012 Wimbledon Championships tennis tournament at the All England Tennis Club in Wimbledon, southwest London, on July 7, 2012.Photo by GLYN KIRK/AFP via Getty Images

However, one former coach of Serena and Venus has named a WTA player as the ‘best player this century.’

Rick Macci names Iga Swiatek as the ‘best player this century’

Rick Macci, who is credited with the early tennis development of the Williams sisters in Compton, California, has surprisingly veered away from Serena when naming the ‘best player this century.’

Despite his long-term relationship with Serena, Macci named current Wimbledon champion Iga Swiatek as the best player of the 21st century.

On X [Twitter], Macci said: “Iga is breaking more records than the Beatles.

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“If you back the truck up and take a look at her career she is the best player this century and her number one hit all time is winning 37 in a row.

“You win 37 in a row in ANYTHING there is no debate your an all time great.“

While Macci’s comments may be surprising, they hold some weight. Swiatek has won seven Grand Slams by the age of 24 and has shown an ability to play on all surfaces despite early struggles on grass.

Iga Swiatek’s 37-match win streak

As Macci noted, Iga Swiatek went on a 37-match winning streak earlier in her career. This 21st century record was previously held by Venus Williams, who won 35 straight matches in 2000.

Venus won Wimbledon, Stanford, San Diego, New Haven, the US Open, and the Olympic Games in Sydney.

Iga Swiatek of Poland kisses the Ladies’ Singles Trophy following her victory against Amanda Anisimova of United States during the Ladies' Singles Final on day thirteen of The Championships Wimbledon 2025 at All England Lawn Tennis and Croquet Club on July 12, 2025 in London, England.Photo by Clive Brunskill/Getty Images

Swiatek, who won junior Wimbledon in 2018, achieved a 37-match win streak in 2022. The Polish star did not lose from February 2022 until the third round of Wimbledon, where she was knocked out by Alize Cornet.

Swiatek, who recently won her first Wimbledon title, will be looking to add a second US Open title to her collection when she competes at the tournament across August and September.