The American world number three triumphed 6-2 6-0 in 65 minutes, winning the second set to love in 27 minutes.
Blinkova, who is ranked 63rd in the world, was no match for Pegula, who won 71 per cent on first serve and 65 per cent on her second. Pegula also generated 10 break points, winning 71 per cent on the Russian's second serve.
The American will take on Romanian 15th seed Irina-Camelia Begu in the round of 16, after she toppled resurgent 2020 Australian Open winner Sofia Kenin 6-1 6-4.
Defending champion and fourth seed Belinda Bencic triumphed in the evening session, breezing past Canada's Katherine Sebov 6-0 6-3 in 62 minutes.
Bencic will meet Shelby Rogers in the third round with the American edging countrywoman Caty McNally 6-7 (4-7) 7-5 6-1.
Ninth seed Madison Keys beat Hailey Baptiste 6-1 6-2, setting up a third-round clash with eighth seed Magda Linette who got past Varvara Gracheva 6-7 (3-7) 7-5 6-4.
Third seed Daria Kasatkina defeated Madison Brengle 6-2 6-1, progressing to face 38th ranked American Bernarda Para who beat Cristina Bucsa 6-3 6-4.
Spaniard Paula Badosa won 7-5 7-6 (8-6) over 2021 US Open runner-up Leylah Fernandez and will face Diana Shnaider who upset fifth seed Veronika Kudermetova 6-4 6-3.
Eugenie Bouchard's campaign at the Copa Colsanitas was halted in the second round with a 6-0 6-7 (7-9) 6-4 loss to fourth seed Kamilla Rakhimova.
It is the first time since the 2012 Stuttgart Open that all four top seeds reached the final four in a WTA 500 event.
Pegula, the top overall seed and the only remaining American, used her commanding serving game to overwhelm 12th seed Paula Badosa 6-3 7-6 (8-6).
She ended up winning 80 per cent of her accurate first serves – compared to 57 per cent for Badosa – and it resulted in the Spaniard producing just one break point opportunity in the match, which she could not take.
Pegula will meet fourth seed and Olympic gold medallist Belinda Bencic next after her relatively comfortable 6-3 6-3 triumph against Russia's Ekaterina Alexandrova.
Switzerland's Bencic needed just 80 minutes to get the job done, creating 12 break point chances compared to Alexandrova's two, while winning the first three games of each set.
After coming into the tournament without consecutive wins since early January, reigning Wimbledon and US Open finalist Ons Jabeur looked back to her best in a dominant 6-0 4-1 (retired) drubbing of Anna Kalinskaya.
Jabeur is yet to lose a set in Charleston, and she will try to keep that the case when she faces Daria Kasatkina in her semi-final.
Kasatkina earned her spot in the final four with Friday's only three-setter, emerging victorious 6-7 (5-7) 6-4 6-2 against Madison Keys in just over two and a half hours.
Pegula, the top-ranked American and the tournament's overall top seed, may have thought it was going to be smooth sailing after collecting a break-to-love in the match's opening game, but it was just the beginning of a two-hour-and-32-minute battle.
Begu played terrific tennis against a world-class opponent, winning 47 per cent of the match's total points, but she shot herself in the foot with eight double faults while Pegula had just one.
With the victory, Pegula booked her place in the quarter-final against Spain's Paula Badosa after her stylish 6-1 6-3 result over Russian 19-year-old Diana Shnaider.
Badosa now has a 4-2 record since the beginning of March, but both of those losses came to the in-form Elena Rybakina in eliminations from both the Indian Wells Open and the Miami Open.
Meanwhile, reigning Wimbledon and US Open finalist Ons Jabeur needed just 82 minutes to dispatch Caroline Dolehide 6-3 7-5, and combined with her opening victory against Lesia Tsurenko it is Jabeur's first consecutive wins since the Adelaide International in early January.
Jabeur will play Anna Kalinskaya in her quarter-final after the Russian upset two-time Australian Open champion Victoria Azarenka 6-4 7-6 (7-5).
It was a strong day for the Russians, as Ekaterina Alexandrova got the better of Julia Grabher 6-4 6-2, and world number eight Daria Kasatkina knocked out Bernarda Pera 6-3 7-6 (7-3).
Olympic gold medalist Belinda Bencic won the longest match of the day in a two-hour-and-45-minute war of attrition against Shelby Rogers 4-6 7-5 6-2, but the Americans had something to cheer for in the late window as Madison Keys advanced past Magda Linette 6-2 3-6 6-1.
Garcia, the world number 10, entered the contest off back-to-back losses for the first time since March, and Collins made it three in a row as she was just a little too good with both her serving and return game.
Collins won 63 per cent of her service points, with Garcia at 52 per cent, and she ended up securing five breaks in the match.
She will play Martina Trevisan in the second round after the Italian defeated Colombian qualifier Camila Osorio 6-3 6-4.
Neither player had an ace in the match, but the big differentiating factor was Trevisan's ability to win points off her second serve, converting 50 per cent of her chances while Osorio won only one of nine (11 per cent).
The only qualifier of the day to get a win was Louisa Chirico, who beat fellow American Alison Riske-Amritraj 1-6 7-5 7-6 (7-5).
Chirico, the world number 196, will be rewarded for her win with a showdown against world number four Paula Badosa.
Madison Keys had no issues dealing with Australian qualifier Ellen Perez 6-1 6-4 in just over an hour, and Coco Vandeweghe defeated Sofia Kenin 6-1 1-6 6-4.
In the last match of the night, Canada's Bianca Andreescu won a two-hour-and-40-minute battle against Russia's Liudmila Samsonova 7-6 (7-1) 4-6 6-2.
Rybakina won the first set comfortably before the Russian hit back for a remarkable turnaround win, 1-6 6-2 6-0 in one hour and 40 minutes.
Seventh seed Kasatkina was the runner-up at last year's Silicon Valley Classic and found her groove to break her Rybakina six times in the second and third sets.
Rybakina sent down three of her four aces for the match in the first set, but Kasatkina adjusted to her serve and won 52.1 per cent return points for the match.
Eighth seed Karolina Pliskova fought back from a slow start to get past Katie Boulter 1-6 7-6 (7-5) 6-3, despite 16 double faults.
American Amanda Anisimova overcame compatriot Ashlyn Krueger 6-2 7-6 (7-5). US pair Madison Keys and Taylor Townsend were also winners.
Third seed Simona Halep and top seed Jessica Pegula were both among the winners in the first round at the Citi Open in Washington DC.
Two-time major winner Halep cruised past Spanish qualifier Cristina Bucsa 6-3 7-5 in one hour and 20 minutes.
Halep, playing her first match since her Wimbledon semi-final loss to Rybakina, fired 19 winners but also 33 unforced errors.
Defending champion Pegula made light work of countrywoman Hailey Baptiste 6-2 6-2 in 73 minutes.
Pegula will face unseeded Australian Daria Saville, who won in three sets over Mirjam Bjorklund, while sixth seed Kaia Kanepi will meet China's Zhu Lin after both won on Monday.
Fifth seed Elise Mertens was a first-round casualty, going down 7-6 (7-4) 6-4 to Ludmilla Samsonova, while Croatian Donna Vekic knocked off seventh seed Mayar Sherif 6-4 6-1.
Six-time major champion Venus Williams played her first singles match in nearly a year but bowed out 4-6 6-1 6-4 to Rebecca Marino.
Losing her opening matches at the sunshine double of Miami and Indian Wells, after only taking five games off Iga Swiatek at the quarter-final in Doha, the world number five improved her head-to-head record with Riske to 5-0.
Sabalenka by no means cruised to victory, though, failing to close the match out at 5-2 in the second set. Riske had four break points to level at 5-5, but the 23-year-old powered through when she needed to, eventually closing out after an hour and 49 minutes.
Second-seeded Paula Badosa of Spain and ninth-seeded American Madison Keys also advanced to the third round at Charleston, with respective wins over Anna Bondar and Ulrikke Eikeri.
Badosa, who made the semi-finals in Charleston last year, overcame a mid-match rain delay to eventually win in an hour and 35 minutes.
Jessica Pegula continued her positive run of form after making the semi-finals in Miami, accounting for Jasmine Paolini with a 6-2 6-1 victory.
Other seeded winners included Belinda Bencic and Alize Cornet, while Elina Rybakina, Ajla Tomljanovic and Shuai Zhang were among seeds who lost on Wednesday.
The weather in South Carolina continued to be a problem at the first WTA clay-court event this season, however, as the match between Ons Jabeur and Emma Navarro was suspended due to heavy rain.
Meanwhile at the Copa Colsanitas in Bogota, Rebecca Peterson was the only seeded player in action on Wednesday, and lost 6-1 6-4 to Germany's Tatjana Maria.
The second seed trailed 4-2 and was a break down in the opening set, but went on to win 11 of the next 13 games to seal a fourth-round clash with either Madison Keys or Emma Navarro.
Sabalenka has dropped just seven games in her opening two matches at Roland-Garros.
Although, it looked like she may lose the opening set when a fortuitous net shot gave Badosa a second break and a 4-2 lead on Court Philippe-Chatrier.
However, she dug deep from 5-3 adrift, winning the last four games to draw first blood.
The reigning Australian Open champion broke her opponent a further two times on the way to a commanding 4-0 advantage in the second.
Badosa did well to save three match points from 0-40 in game six, but the Spaniard could not rescue a fourth as her opponent continued her surge into the second week.
Data Debrief: Sabalenka completes top four in last 16
Following on from her victories when they met in Miami and Stuttgart earlier this season, Sabalenka became the first player to beat Badosa three times at WTA events in a calendar year.
Joining Iga Swiatek, Coco Gauff and Elena Rybakina, this marks the first time since 2013 that the top four seeds are through to the last 16 in the women's singles at Roland-Garros.
A 6-4 1-6 7-5 victory for Madison Keys over top seed Sabalenka capped a day of upsets in Berlin.
American Keys fought back from a set down to bundle the world number four out in an hour and 29 minutes.
The battling Sabalenka saved 10 break points but was unable to avoid an early exit in the inaugural grass-court event.
Second seed Svitolina started her grass-court season with a 6-4 7-5 defeat to Ekaterina Alexandrova.
Russian Alexandrova fended off seven set points in the second set before sending the world number six, who was given a first-round bye, packing.
Svitolina, playing her first match since crashing out of the French Open in the third round, became the fourth top-10 scalp for Alexandrova, who will face Belinda Bencic in her fifth quarter-final of the year.
Andreescu's first match on grass since Wimbledon qualifying three years ago ended in a 7-6 (7-2) 7-5 loss to Alize Cornet.
The third seed from Canada parted with her long-time coach Sylvain Bruneau after she was beaten by Tamara Zidansek in the first round at Roland Garros and was unable to hit the ground running on grass.
Bencic, the fifth seed, advanced with a 6-3 5-4 success over Petra Martic.
Two-time Wimbledon champion Kvitova, the 12th favourite in the United Arab Emirates, eased past Italy's Martina Trevisan 6-2 6-1 to make a dominant start.
World number 15 Samsonova was made to work to beat Paula Badosa, winning 6-7 (3-7) 7-6 (7-5) 6-4 to tee up a clash with Qinwen Zheng, who overcame compatriot Zhang Shuai in straight sets.
Samsonova's triumph took three hours and 22 minutes, the longest match of the WTA Tour season thus far, in a thrilling first-round encounter between two top-20 players.
"Playing against Paula is always tough," 14th seed Samsonova said in her on-court interview. "She's doing unbelievable, so I'm really proud that I stayed on the court until the end.
"I think I'm growing match after match, day by day. I know it's a long journey, and I hope to continue like that."
Barbora Krejcikova, the 2021 French Open champion, cruised into the last 32 with a comfortable 6-4 6-2 victory over Irina-Camelia Begu as she aims to go one better than her runners-up finish two years ago in Dubai.
Another routine victory saw American Madison Keys ease past Jasmine Paolini 6-1 6-1, but there was no such luck for 2020 Australian Open champion Sofia Kenin.
She was dispatched 6-1 6-1 by world number 26 Marie Bouzkova, while Amanda Anisimova claimed a 6-3 6-2 win over veteran two-time grand slam finalist Vera Zvonareva.
Viktoriya Tomova had too much for Kaia Kanepi in a 6-3 6-1 success, with her reward a second-round clash against third seed Jessica Pegula.
World number four Pegula lost to the in-form Iga Swiatek in the Qatar Ladies Open final on Saturday, and Leylah Fernandez will face the Pole next after beating Julia Grabher 6-4 6-2.
Frenchwoman Tan, who is ranked outside the top 100, toppled the second seed in one hour and 46 minutes, winning 6-4 1-6 6-1.
In a seesawing battle, Tan's shotmaking and deft touch was a highlight, helping her steady after emphatically dropping the second set, before winning the first five games of the final set.
The win was Tan's first-ever victory against a top 30 player, qualifying her for the second round where she will play China's Wang Qiang who won 6-2 6-1 over Lauren Davis.
American sixth seed Sloane Stephens did not have such problems in her first-round encounter with qualifier Brenda Fruhvirtova, triumphing 6-2 6-2.
The 14-year-old Czech had enjoyed a good qualifying run but was thwarted by the 2017 US Open champion in 58 minutes.
Fruhvirtova had become the youngest player to compete in a WTA Tour main draw match since Keys in April 2009 at Ponte Vedra Beach.
Fifth seed Nuria Parrizas Diaz bowed out 6-1 6-4 to Slovakia's Ana Karolina Schmiedlova in one hour and 10 minutes. Schmiedlova will face Anastasia Potapova who progressed 6-4 2-2 after Lesia Tsurenko retired.
Japanese seventh seed Misaki Doi also exited, going down 4-6 7-5 6-4 to Marie Bouzkova in the late match, setting up a second-round date with qualifier Lucia Bronzetti who edged American wildcard Caty McNally 6-7 (5-7) 6-3 6-3.
Zheng Qinwen was another seeded casualty, with the Chinese eighth seed going down 6-3 2-6 6-2 to Anna Kalinskaya.
The 14th seed was undone by the French qualifier despite Dodin sending down 10 double faults.
The 6-3 1-6 6-2 success was Dodin's first over a top-25 player this season.
Former U.S. Open finalists and 16th seed Madison Keys was also a first-round casualty, going down 6-3 6-3 to Canadian Rebecca Marino.
Toronto-born Marino, currently ranked 220th in the world, won in one hour and six minutes, converting four of her eight break points, while she saved four from five too.
However, there were no such problems for Ons Jabeur, the 13th seed strolling to a 6-1 6-3 victory over Clara Burel.
Eleventh seed Maria Sakkari also had a routine day, her opponent Marie Bouzkova unable to continue with Sakkari ahead 6-4 3-1.
An Olympic gold medallist in the doubles at Tokyo 2020, Katerina Siniakova had more to celebrate in the singles with a 6-1 6-3 win over long-time rival Jelena Ostapenko.
Elsewhere in the draw, Paula Badosa, Sorana Cirstea, Amanda Anisimova, Nadia Podoroska and Fiona Ferro all progressed.
Not since winning the 2017 Australian Open had Williams clinched silverware – the 23-time grand slam champion a runner-up at Wimbledon (2018 and 2019) and the US Open (2018 and 2019), while she retired in the 2019 Rogers Cup final.
However, Williams ended her drought by defeating fellow American Jessica Pegula 6-3 6-4 in the women's final in New Zealand.
"It feels good. It's been a long time. I think you could see the relief on my face," Williams said during her on-court interview before announcing she will donate her prize money (and a dress from each of her matches) to the bushfire relief effort in Australia.
Williams was almost flawless against Pegula, stepping up her preparations for the upcoming Australian Open with two aces and just one break of serve to capture her 73rd WTA crown – a record stretching across four decades after winning her first in 1999.
After a sluggish start, which saw the top seed fall 3-1 behind in the opening set, Williams eventually found her range en route to the 38-year-old's first trophy as a mother.
After snapping a sequence of five defeats in finals since her 2017 triumph at the Australian Open, Williams will look to equal Margaret Court's record of 24 slam titles at Melbourne Park.
Meanwhile, defending champion and second seed Karolina Pliskova won the Brisbane International for a second straight year after outlasting Madison Keys in three sets.
Pliskova prevailed 6-4 4-6 7-5 over eighth seed Keys for her third victory at the WTA Premier event in Brisbane.
Stephens, who is currently ranked 73rd in the world, having been number three on the WTA Tour in 2018, triumphed 6-7 (5-7) 7-5 6-1 over Watson in two hours, 50 minutes on Wednesday.
In a see-sawing match, there were six breaks in the opening set, as Watson got the edge early on Stephens' serve at the WTA Premier 1000 event.
Stephens steadied by claiming a late break in the second to level the match, before dominating the third set.
Playing at her 10th Indian Wells Open, Stephens won seven consecutive games after the match was 5-5 in the second set.
"After the first set, that was disappointing to lose that one, but I felt like it was a battle and I was still in the match," Stephens said. "I knew I had to keep fighting and that's what I did, and I'm just really pleased to have squeaked out a win here."
KEYS ON SONG IN OPENER
Former world number seven Madison Keys moved through to the second round with a 6-0 7-5 win over fast-finishing Estonian veteran Kaia Kanepi.
American Keys won 21 consecutive points as part of a streak where she clinched the first nine games of the match, withstanding Kenapi's late push.
Keys will take on Russian ninth seed Anastasia Pavlyuchenkova for a spot in the third round.
SAMSONOVA, MARTIC, ROGERS AND PUTINTSEVA PROGRESS
Liudmila Samsonova, who made the fourth round at Wimbledon earlier this year, needed more than two hours to get past Ukrainian qualifier Kateryna Kozlova 6-4 7-6 (8-6).
Samsonova will face countrywoman and 25th seed Veronika Kudermetova in the second round.
Petra Martic won through to take on second seed Iga Swiatek with a 6-4 6-4 victory over American wildcard Katie Volynets.
Ash Barty's US Open conqueror Shelby Rogers claimed her 25th win for the year, getting past Ukrainian Anhelina Kalinina 7-6 (7-2) 6-2, while Yulia Putintseva won 7-6 (7-2) 6-1 over experienced German Andrea Petkovic to set up a showdown with fellow Kazakh player and 13th seed Elena Rybakina.
The Ukrainian defeated Ana Bogdan 7-5 6-2 on Saturday to reach the last 16 for the sixth time in her career.
Both players struggled on serve, with 11 breaks in total during the match, but it was Svitolina who ultimately emerged triumphant after a back-and-forth contest and a rain delay, firing 28 winners.
Fifteenth seed Svitolina will now hope to halt the Paris charge of fourth seed Rybakina, who is yet to drop a set at the tournament so far. It will be a tough ask, but Svitolina does lead the head-to-head 2-1.
An all-American clash between Madison Keys and Emma Navarro on Court Suzanne-Lenglen was one of the other standout matches.
Navarro had never before reached the fourth round at a major, while Keys was a former semi-finalist at Roland-Garros.
But it was Navarro who claimed a hard-fought victory, getting the better of two tie-breaks to win 7-6 (7-5) 7-6 (7-3) to book a huge clash against second seed Aryna Sabalenka.
Jasmine Paolini is also through to round four after seeing off former US Open champion Bianca Andreescu 6-1 3-6 6-0.
Mirra Andreeva, meanwhile, is the youngest player to reach the French Open last 16 since Nicole Vaidisova in 2006 after beating Peyton Stearns in straight sets.
The 17-year-old raced to a 6-2 6-1 win in only 67 minutes.
Sabalenka and Rybakina had earlier completed routine victories over Paula Badosa and Elise Mertens respectively.
The top seed, who made it to the final last year, dropped a set for the first time in this tournament before recovering to win 4-6 6-0 6-2 in a match that lasted just short of two-and-a-half hours.
These two players met in the French Open semi-finals last year and 11th seed Haddad Maia was eyeing an upset when she fought back from 4-1 down to claim the opener.
But Swiatek dropped serve just once in the next two sets as she assumed full control and swept to victory, powered by winning eight straight games from the start of the second set.
Data Debrief: Swiatek statistics up there with the best
Up next for Swiatek will be a last-four clash against either Ons Jabeur or Madison Keys, who play later on Tuesday. That will be her 15th WTA 1000 semi-final appearance since 2020, with no other player having made it to double figures (Aryna Sabalenka and Maria Sakkari are the next best on eight each).
Beating Haddad Maia also means Swiatek has equalled Serena Williams and Maria Sharapova as the fastest player to reach 25 WTA 1000 wins on clay, doing so in just 29 matches.
And Swiatek's emphatic second set saw her tie Coco Gauff for the most number of 6-0 sets won so far this year. They both have seven, just ahead of Sabalenka (five).
Defending champion Sabalenka plays Mirra Andreeva in the last eight on Wednesday after battling past Danielle Collins in three sets. All three of her wins so far have been in deciding sets.
The other last-eight clash is between Elena Rybakina and Yulia Putintseva.
Swiatek was irrepressible against the 18-year-old American, extending her head-to-head dominance to 4-0 with a 6-0 6-3 victory in 66 minutes.
The Pole won the first eight games of the match and always appeared in control with her reliable forehand a key feature.
Swiatek laced 13 winners with only nine unforced errors, breaking Gauff five times. The American committed 26 unforced errors for the match.
The victory is Swiatek's 62nd of the season, moving her closer to Angelique Kerber's 2016 mark of 63.
Swiatek will face fourth seed Jessica Pegula in the semi-finals as the Pole aims for her eighth WTA title of the season.
Pegula secured her berth in the final four with a 6-4 7-5 victory over compatriot Madison Keys in their first-ever meeting in one hour and 34 minutes.
Third seed Aryna Sabalenka was a surprise casualty as Croatian qualifier Donna Vekic continued her excellent week with a 6-4 6-7 (5-7) 6-1 in two hours and 37 minutes.
World number 77 Vekic has beaten former world number three Maria Sakkari and two-time major finalist Karolina Pliskova this week.
Second seed Paula Badosa was also bundled out by American Danielle Collins 7-6 (7-5) 6-4. Collins will meet Vekic in the last four.
The 2022 French Open and US Open champion triumphed 6-4 4-6 6-1 in two hours and two minutes, bouncing back strongly after losing the second set.
Zheng's power and forehand top spin proved challenging for the Pole, who was solid from the baseline to secure her 11st tour quarter-finals appearance this season.
The Chinese had broken Swiatek to lead 1-0 in the third set, but the top seed responded in trademark style, improving her record in the United States this season to 21-1.
Swiatek will take on eighth seed Coco Gauff in the quarter-finals, with the match-up marking a re-match of this year's French Open final.
Gauff worked her way into the last eight with a 6-4 4-6 6-3 victory over 2019 US Open champion Bianca Andreescu.
The 18-year-old American also had to fight back from a set down in the third set to win in a match that lasted just over two-and-a-half hours.
Third seed Aryna Sabalenka fought back from a lopsided opening set to knock out American Sloane Stephens 1-6 6-3 6-2 in two hours and one minute. The Belarussian will take on Donna Vekic in the next round.
Second seed Paula Badosa eased into the last eight, winning in 53 minutes against American qualifier Louisa Chirico 6-0 6-3. Badosa will face Danielle Collins in the quarter-finals.
Madison Keys triumphed over eighth seed Daria Kasatkina 6-4 6-3 in one hour and 27 minutes to secure a quarter-final date with fourth seed Jessica Pegula.
Swiatek had been forced to fight back from a set down against Beatriz Haddad Maia in the quarter-finals, but there was no slow start on Thursday as she broke Keys' serve to love at the first attempt.
Only in the fifth game, when Keys failed to convert two break points, was Swiatek troubled in a 31-minute opener, and she carried that momentum into the second set with another early break.
Having eliminated Coco Gauff and Ons Jabeur on a deeply impressive run, Keys had no answer for Swiatek's power as she clinically worked her way through the second set, the American's forehand running long on match point to seal a routine win for the world number one.
Having lost last year's final against Aryna Sabalenka, Swiatek could face a rematch against the defending champion, who takes on Elena Rybakina in Thursday's other semi-final.
Data Debrief: Swiatek surpasses Serena
Saturday's final will be Swiatek's 11th at WTA 1000-level, the Pole going all the way on 37.9 per cent of her 29 main-draw entries at that level. That is a better ratio than 23-time grand slam champion Serena Williams managed in her glittering career, the American doing so at 18 of 49 WTA 1000 tournaments (36.7 per cent).
Swiatek has now played eight matches in 2024 without dropping a single game on her own serve, a tally only matched by her possible final opponent Sabalenka on the WTA tour.
Poland trailed after Lorenzo Musetti and Matteo Berrettini secured wins against Daniel Michalski and Hubert Hurkacz respectively, only for Swiatek and Magda Linette to level things with respective singles victories over Martina Trevisan and Lucia Bronzetti.
That sent the Brisbane city final to a decider in the mixed doubles, which Swiatek and Hurkacz won with ease 6-1 6-2 against Musetti and Camilla Rosatello, though there was a pause in the second set to dry rainfall on the court.
Despite defeat, Italy also advanced to the final four as the city finals loser with the best record.
It was more routine in Sydney as the United States eased to a 4-1 win against Great Britain.
Madison Keys came from a set down to beat Katie Swan, while Jessica Pegula eased past Harriet Dart 6-2 6-0 after Cameron Norrie had defeated Taylor Fritz in three sets.
Despite going a set behind, Frances Tiafoe came back to beat Dan Evans 3-6 7-5 6-3 to clinch the win for his country, before Pegula and Fritz added some gloss after beating Dart and Evans in the mixed doubles.
The third city final in Perth included a thriller as Greece's Stefanos Tsitsipas beat Borna Coric 6-0 6-7 (4-7) 7-5. Donna Vekic had no trouble getting Croatia on the board as she eased past Despina Papamichail 6-2 6-0.
Maria Sakkari put Greece 2-1 ahead when she beat Petra Martic 6-3 6-3, but Borna Gojo defeated Stefanos Sakellaridis in straight sets to make it 2-2.
However, Greece secured the win and their place in the last four after the pairing of Sakkari and Tsitsipas saw off Martic and Gojo 7-6 (8-6) 6-4.
Greece will take on Italy in the semi-finals, while Poland face the USA, with both taking place in Sydney on Friday.
The world number one took just 76 minutes to wrap up a commanding 6-1 6-3 win - matching the scoreline which saw her overcome the American in the Madrid Open last four a fortnight ago.
Swiatek broke her opponent four times and saved all 10 break points she faced on the way to setting up a semi-final showdown with either Coco Gauff or Qinwen Zheng.
Yet to drop a set this week, the Pole remains on course to complete a hat-trick of titles in Rome and land her fourth silverware of 2024, in which she now boasts a 36-4 record.
Data debrief
Reaching her 16th WTA 1000 semi-final from 30 main draws entered, Swiatek (53.3 per cent) surpasses Serena Williams (53.1 per cent, 26 from 49) for the highest rate of last-four appearances in such tournaments since the format's introduction in 2009.
The Pole also took her tally of WTA match wins on clay to 75 from 85, with only Monica Seles, Nancy Richey (both 80), Chris Evert (81) and Margaret Court (82) reaching that figure on surface in fewer matches during the Open Era.
