The quarter-final in Rome was a repeat of Swiatek's recent semi-final clash with America's Keys in Madrid, which ended with the same scoreline.

World number one Swiatek broke serve in the opening game, and while Keys won her next service game to love to make it 2-1, the Polish top-seed won the next four games to take the first set in 26 minutes.

Swiatek needed just one break in the second set, which gave her a 3-1 lead, and when the Pole saved four break points in the next game to hold serve, Keys' chance of a comeback ended.

"Honestly I felt really good today, even if I that knew one or two points could change everything," Swiatek said.

"I'm glad that I served well because I think when we were kind of even in the games sometimes, I could win two points just by serving.

"It's something that doesn't happen often in my game, so today was a good day in terms of that."

Swiatek is aiming to win her fourth title this year having already won the Qatar Open, Indian Wells and the Madrid Open.

She will face Gauff on Friday after the American beat China's Zheng Qinwen 7-6(4), 6-1 in the other quarter-final on Tuesday.

"(Swiatek) is a tough opponent to play, especially on clay. There's a reason why she's number one," Gauff said.

"But I feel like I'm getting better with each match. I'm really excited to play the semi-final."

In the remaining quarter-finals on Wednesday, world number two Aryna Sabalenka will face ninth seed Jelena Ostapenko before Victoria Azarenka plays American 13th seed Danielle Collins.