Slowly, point by point, Williams relaxed, started to better predict and return Pliskova's powerful serves and began controlling points and winning games.
"Today I just really couldn't get anything to connect".
Pliskova had never been past the third round at a Grand Slam when she shocked Serena Williams in the 2016 US Open semis. Williams missed the 2017 edition as she gave birth to her daughter, Alexis Olympia.
'I just want to be able to get past the semis here. I don't know. It's going to be a close match, I think.
Yet one megastar remains at the US Open: Serena Williams, looming like Gulliver over the Lilliputians.
Serena Williams will play for her record-tying 24th Grand Slam singles title after advancing to the U.S. Open final with a 6-3, 6-0 victory over Anastasija Sevastova.
Those choruses resonated in the arena after key points, such as each time del Potro erased one of Isner's break chances, three in all.
World number three Stephens, refused to blame the punishing afternoon heat and humidity for her lapses against Sevastova, including an inability to convert any of seven break chances in the opening set. The Czech, playing in her third straight US Open quarter-final, applied some pressure with a backhand victor, Serena sent a down the line victor wide, double-faulted and succumbed on the third break point chance.
The 18th seeded Latvian is now the only hurdle standing between Williams and a place in Saturday's final where the other side of the draw has also been cleared of potential trouble with 14th seeded American Madison Keys the highest ranked threat remaining.
"She's been playing really well for actually a long time", Williams said of her semi-final opponent. It just was a really tough day. We showed some nerves in the end, but it's normal.
Defending champion Sloane Stephens has been knocked out of the U.S. Open in straight sets. It is the first time he won a match after that kind of start. Tough loss previous year.
Soon after that, Williams went from trailing 4-2 to not only taking the first set but also leading 4-0 in the second.
Federer, a 37-year-old Swiss veteran, is a five-time Open champion.
Williams first won at the U.S. Open in 1999 and has won the tournament six times.
Follow the Race to ATP Finals this fall on Tennis Channel PLUS. "I have no words", Serena admitted in the post-match on-court interview. "I have so much respect for Roger and everything he's done in his career". "I'm here to do my best".
It took Williams a while to get into it but it was inevitable that the American eventually would fight back, and in this game she did delivering punishing hard forehands which forced the errors out of Pliskova.
"I'm very sorry for Dominic", Nadal said. "The feet weren't moving".
When someone urged her to raise her level in the second set, Stephens replied, "I'm trying!" "Right now you're so in the tournament and you don't feel it".