Earlier, Pegula secured a breezy 6-2, 6-3 victory over the already-eliminated Jasmine Paolini and said she would work out a strategy for her next opponent despite knowing there was a slim chance of an exit if Gauff prevailed in three sets.
Former world number one Lleyton Hewitt of Australia has pulled out of the French Open because of a left ankle injury, organisers said on Sunday.
Rain played spoilsport at the French Open for the second day running when a torrential downpour stopped the action for a second time on Monday.
Spain's Rafa Nadal beat Serbia's Novak Djokovic 6-4, 6-3, 2-6, 7-5 to win a record seventh French Open tennis title on Monday.
Sania Mirza and Mahesh Bhupathi inched towards their second Grand Slam title together as they progressed to the mixed doubles semi-finals of the French Open after shocking second seeds Kveta Peschke and Mike Bryan.
Former champion Francesca Schiavone made a third-round exit from the French Open on Saturday when she was beaten, for the second time in a month, by American left-hander Varvara Lepchenko.
India's poor run at the French Open continued as Leander Paes and his Austrian partner Alexander Peya crashed out of the second round of the men's doubles event after losing to Mikhail Elgin of Russia and Uzbekistan's Denis Istomin 4-6, 1-6.
Jannik Sinner and Carlos Alcaraz are poised to reignite their rivalry at the ATP Finals, with the year-ending championship that begins on Sunday expected to produce another title showdown between the pair in a season that has belonged to them.
Factbox on American second seed Coco Gauff, who defeated Belarusian world number one Aryna Sabalenka
Underarm serve could be an effective weapon in halting Rafael Nadal's annual rampage on clay most just chuckled.
"Think of it from a players' perspective. Some are hoping to reach the second week of a major but some don't even make it to the first week of the event. That's tough to take.
Djokovic did not play badly in the final but it took him 55 minutes before he registered his first game in what turned out to be a mauling.
The men's doubles pair of Satwiksairaj Rankireddy and Chirag Shetty continued their impressive run, progressing to the semi-finals with another stunning victory, but it was curtains for Saina Nehwal at the US $700,000 French Open, in Paris, on Friday.
Serena Williams likes proving people wrong and intends to surprise the sceptics at next month's French Open.
Images from Day 9 of the French Open in Paris on Monday.
Tennis fans expressed frustration that the players weren't getting better crowds.
Srikanth fought hard for 55 minutes against second seed Chou Tien Chen of Chinese Taipei
French sports daily L'Equipe said at least one of the 152 samples tested during the tournament had been positive.
Simona Halep has been in red-hot form and the absence of top-ranked Australian Ash Barty, who won her maiden Grand Slam in Paris last year, and US Open champion Naomi Osaka, will boost her chances further.
World number six Milos Raonic has withdrawn from the French Open having failed to recover from a foot injury, the 24-year-old announced on Thursday.
The 13th seeded Czech proved too strong for Serb, who lifted the Suzanne Lenglen Cup in 2008, winning 7-5, 6-4.
Indian ace Saina Nehwal started her campaign at the French Open Super Series on a positive note, thrashing Jie Yao of Holland in straight-games to reach the second round of the women's singles event at Paris on Wednesday.
French Open champion Coco Gauff captured her third WTA 1000 title and first in Wuhan after rallying from two breaks down in the second set to defeat fellow American Jessica Pegula 6-4, 7-5 in Sunday's final.
Former champion Ana Ivanovic was at her brilliant, aggressive best on Tuesday. The seventh seed swept aside Ukraine's Elina Svitolina 6-3, 6-2 to storm into the French Open semi-finals.
Alize Cornet fought tooth and nail but the local favourite's French Open run came to an end when she was knocked out 6-2, 7-6(9) in the fourth round by Ukrainian 19th seed Elina Svitolina on Sunday.
Images from all the action from Day 1 of the French Open played at Roland Garros in Paris on Sunday
The popular Romanian, who had lost three major finals before Saturday, showed signs of nerves at first but recovered to outclass her 10th-seeded opponent.
A summary of Friday play at the French Open.
The Indian pair of Treesa Jolly and Gayatri Gopichand retained the women's doubles crown but Kidambi Srikanth's hopes of snapping an eight-year title drought went up in smoke as he suffered a heartbreaking loss in the final of the Syed Modi International Super 300, in Lucknow on Sunday.
Images from the French Open Men's singles final between Roger Federer and Rafa Nadal at Roland Garros.
Sania Mirza stormed into her first Grand Slam doubles final. She and her Russian partner Elena Vesnina defeated the American duo of Liezel Huber and Lisa Raymond in a thrilling three-setter in the semi-finals of the French Open in Paris on Wednesday.
Indian Davis Cupper Rohan Bopanna and his Pakistani partner Aisam-ul-haq Qureshi advanced to the French Open men's doubles quarter-finals after a straight-set win over Andrey Golubev of Kazakhstan and Denis Istomin of Uzbekistan. The fifth seeded Indo-Pak pair beat their unseeded opponents 6-3, 7-5 in a third round match that lasted 69 minutes.
Unseeded Arantxa Rus of the Netherlands produced the biggest upset of the 2011 French Open when she knocked out second seed Kim Clijsters in the women's singles second round.
India's Somdev Devvarman crashed out of the French Open in Paris on Tuesday, after losing in straight sets to Croatian big-serving giant Ivan Ljubicic in the first round.
Serena Williams is unlikely to win a record equalling 24th Grand slam title on the claycourts of Roland Garros, although her chance will come, the American's long-time coach Patrick Mouratoglou said on Friday.
The French Open is elevating its total purse at Roland Garros to about $63.7 million, an increase of 5.21 percent compared to last year.
IMAGES from the UEFA Champions League matches played on Tuesday
World number one Andy Murray shrugged off a sluggish start to reach his fifth French Open semi-final with a 2-6, 6-1, 7-6(0), 6-1 defeat of Japan's Kei Nishikori.
Spaniard Garbine Muguruza withdraw from the Italian Open semi-finals with a neck injury on Saturday, eight days before she is due to start the defence of her French Open title at Roland Garros.
Serena Williams played with fire at the French Open on Thursday but the world number one pulled through to the third round with a 5-7, 6-3, 6-3 win against unheralded German Anna-Lena Friedsam.