Tennis Betting Tips: Clinical Cirstea at it again while Swiatek sweats it out on Sunday

I turn my attention to the women's singles on Day 8 of the 2026 French Open, with the quarter-finals now in sight.

Below are my Tennis Betting Tips for Sunday 31 May, as the action intensifies at Roland-Garros...

Total Games - Under 18.5 in Sorana Cirstea vs Xiyu Wang @ 6/5

Sorana Cirstea absolutely crushed Solana Sierra in their third-round meeting on Friday, dropping just six points on serve in a 6-0, 6-0 victory.

The 36-year-old, who announced last December that she would be retiring at the end of 2026, has been in sensational form at Roland-Garros, losing just seven games en route to the last 16.

Cirstea beat home wildcard Ksenia Efremova 6-3, 6-1 in the opening round before dispatching German Eva Lys 6-3, 6-0 in the second, and she looms large for Chinese No. 6 Wang Xiyu, who also hasn't dropped a set so far in Paris.

Wang overcame Montenigrin Danka Kovinic 6-3, 6-1 in the first round to set up a second-round tie with American Hailey Baptiste, who was forced to retired at 4-5 in the first set due to a suspected knee injury.

Waiting for Wang in the third round was Yuliia Starodubtseva, who had taken out World No. 2 Elena Rybakina 3-6, 6-1, 7-6 in the second.

Starodubtseva was no match for the 25-year-old, though, who won 6-3, 7-5 on Friday to reach the last 16 of a Grand Slam for the first time.

I don't expect Cirstea to show Wang any mercy on Sunday, and while another double bagel feels far-fetched, I'm confident the Romanian can get the job done with the minimum of fuss, booking her ticket to the quarter-finals in fewer than 19 games.

Set Betting - Iga Swiatek 2-1 vs Marta Kostyuk @ 3/1

Backing against an Iga Swiatek straight-sets victory at Roland-Garros is rarely advisable, but Marta Kostyuk's clay-court form this year justifies some bravery, and at 3/1, a 2-1 win in favour of the Pole is the only selection jumping off the page for me here.

Four-time French Open champion Swiatek has endured a challenging year so far, going beyond the quarter-finals of a tournament just once, in Rome earlier this month, when she was beaten 4-6, 6-2, 2-6 in the semis by Ukrainian No. 1 Elina Svitolina.

Swiatek, who celebrates her 25th birthday on Sunday, has made light work of her opponents so far in Paris, though, beating Aussie Emerson Jones (6-1, 6-2), Czech Sara Bejlek (6-2, 6-3) and fellow Pole Magda Linette (6-4, 6-4).

French Open Odds

The quality of her opponents has been rising as the tournament progresses, however, and Linette did take eight games off her on Friday, breaking the third seed's serve on three occasions, and an in-form Kostyuk may sense that Swiatek is not as invincible as she once was at Roland-Garros.

Kostyuk is 14-0 on clay this year, winning titles in Rouen and Madrid, dropping just three sets across three tournaments.

The Ukrainian No. 2 beat ninth seed Mirra Andreeva 6-3, 7-5 in the final of Madrid earlier this month, having beaten fifth seed Jessica Pegula 6-1, 6-4 in the second round.

In Paris, the 23-year-old has overcome Spaniard Oksana Selekhmeteva (6-2, 6-3), American Katie Volynets (6-7, 6-3, 6-3) and Swiss Viktorija Golubic (6-4, 6-3) so far, but Swiatek, of course, represents several steps up in class from those opponents, so she'll have to raise her game again on Sunday, which she has proved she can do against top players in the past.

Ultimately, I expect Swiatek to make the quarters, but at 3/1, I'll back a competitive contest.

Find more Tennis Betting Tips here at Betfred Insights