Serena Williams sees off Karolina Pliskova to reach semifinals

It is the first time the six-time champion has beaten a top-10 opponent since returning from maternity leave.

The victory ensured the American got some measure of revenge for her 2016 US Open semifinal loss against the Czech.

The 36-year-old Williams overcame a 4-2 deficit in the first set to see off Pliskova in one hour and 23 minutes and reach the last four at Flushing Meadows for the 12th time in her career.

Williams -- aiming to win a first grand slam since giving birth to her daughter last September to tie Margaret Court's all-time record of 24 major wins -- will next play Latvia's Anastasija Sevastova, who beat defending champion Sloane Stephens 6-2 6-3 earlier Tuesday.

'I was having a baby at this time last year so I really have nothing to prove,' Williams told the Arthur Ashe crowd after the win.

'I really feel now that I am playing free.'

READ: Nadal beats Thiem in five-set thriller

'I felt so bad I wasn't winning'

Williams struggled at the start of an error-strewn first set -- in which she made 22 of her 30 unforced errors -- before going on an eight-game run to secure victory over the 2016 finalist.

After the match Williams said she had taken confidence from the backing of a partisan crowd, which included Billie Jean King, actor Michael Keaton and director Spike Lee.



'The crowd was really for me and I felt so bad that I wasn't winning,' she said. 'I said, 'I got to try even harder.''

Williams' coach Patrick Mouratoglou said after a 'tight' start the second set 'was like a second match.'

Taking down Pliskova, who enjoyed a brief spell as world No.1 in 2017, was Williams' toughest test of the tournament so far, having already dispatched her sister, Venus -- seeded one higher than Serena at 16 -- and the unseeded Estonian Kaia Kanepi, Carina Witthoeft of Germany and Poland's Magda Linette.

Her last-16 match against Kanepi is the only time any of Williams' matches thus far have gone beyond two sets.

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Though her ranking suffered due to her truncated 2017 season and she came to Flushing Meadows ranked 28th in the world, Williams' dazzling form means she'll be confident of rising up again.

She could be ranked as high as 11th by the end of play Saturday, should she make 2018 her seventh US Open crown.

Taking down Pliskova, who enjoyed a brief spell as world No.1 in 2017, was Williams' toughest test of the tournament so far, having already dispatched her sister, Venus -- seeded one higher than Serena at 16 -- and the unseeded Estonian Kaia Kanepi, Carina Witthoeft of Germany and Poland's Magda Linette. Her last-16 match against Kanepi is the only time any of Williams' matches thus far have gone beyond two sets. READ: Nadal beats Thiem in five-set thriller The victory ensured the American got some measure of revenge for her 2016 US Open semifinal loss against the Czech. After the match Williams said she had taken confidence from the backing of a partisan crowd, which included Billie Jean King, actor Michael Keaton and director Spike Lee. The 36-year-old Williams overcame a 4-2 deficit in the first set to see off Pliskova in one hour and 23 minutes and reach the last four at Flushing Meadows for the 12th time in her career. Though her ranking suffered due to her truncated 2017 season and she came to Flushing Meadows ranked 28th in the world, Williams' dazzling form means she'll be confident of rising up again. The 36-year-old Williams overcame a 4-2 deficit in the first set to see off Pliskova in one hour and 23 minutes and reach the last four at Flushing Meadows for the 12th time in her career. Visit CNN.com/sport for more news and features Williams' coach Patrick Mouratoglou said after a 'tight' start the second set 'was like a second match.' Williams struggled at the start of an error-strewn first set -- in which she made 22 of her 30 unforced errors -- before going on an eight-game run to secure victory over the 2016 finalist. Visit CNN.com/sport for more news and features Williams' coach Patrick Mouratoglou said after a 'tight' start the second set 'was like a second match.' It is the first time the six-time champion has beaten a top-10 opponent since returning from maternity leave. It is the first time the six-time champion has beaten a top-10 opponent since returning from maternity leave. The victory ensured the American got some measure of revenge for her 2016 US Open semifinal loss against the Czech. Though her ranking suffered due to her truncated 2017 season and she came to Flushing Meadows ranked 28th in the world, Williams' dazzling form means she'll be confident of rising up again. Taking down Pliskova, who enjoyed a brief spell as world No.1 in 2017, was Williams' toughest test of the tournament so far, having already dispatched her sister, Venus -- seeded one higher than Serena at 16 -- and the unseeded Estonian Kaia Kanepi, Carina Witthoeft of Germany and Poland's Magda Linette. She could be ranked as high as 11th by the end of play Saturday, should she make 2018 her seventh US Open crown. 'I felt so bad I wasn't winning' After the match Williams said she had taken confidence from the backing of a partisan crowd, which included Billie Jean King, actor Michael Keaton and director Spike Lee. She could be ranked as high as 11th by the end of play Saturday, should she make 2018 her seventh US Open crown.

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