So far, so good for former World No.1 Serena Williams.

The 23-time Grand Slam singles champion and 14-time Grand Slam doubles champion Williams kept her return to the Hologic WTA Tour rolling, as she and Ons Jabeur earned a 6-2, 6-4 quarterfinal win over Shuko Aoyama and Chan Hao-ching in the Rothesay International doubles draw.

Playing in her first event on tour since suffering an injury at last year's Wimbledon, the 40-year-old Williams has found a winning combination with by pairing with singles World No.3 Jabeur for the first time. 

Words from the winners: "For me, it felt really good," Jabeur said in post-match press. "We played much better [than in the opening round]. I think we are getting used to each other now. I am ready for more tournaments, to be honest with you."

"Me too," Williams responded.

"I have had some really good training leading up to Wimbledon and up to this tournament, and really hitting the ball well and just working out, and it's been working. It's just been connecting. ... I feel like I have been serving well so that's been really good. Working really hard on that."

Said Jabeur: "I think I'm learning from the best how to serve much better."

Fast facts: After a close first-round win against Marie Bouzkova and Sara Sorribes Tormo, Williams and Jabeur had an easier time in the quarterfinals, knocking out Doubles World No.10 Aoyama and No.49 Chan in just 65 minutes.

After winning a routine first set without facing any break points, Williams and Jabeur were tested much more in the second set. However, Aoyama and Chan went 0-for-9 on break points in that set, with aces by Williams erasing four of those opportunities.

Looking ahead: Williams and Jabeur will next take on Aleksandra Krunic and Magda Linette in the semifinals. Unseeded Krunic and Linette took just 57 minutes to upset No.2 seeds Gabriela Dabrowski and Giuliana Olmos 6-1, 6-3 in their quarterfinal clash.

Ostapenko moves forward after Keys retires

In evening singles play, defending champion and No.8 seed Jelena Ostapenko reached the quarterfinals after No.11 seed Madison Keys retired from their match due to an abdominal injury. Ostapenko had taken the first set 6-3 when Keys stopped the encounter due to her ailment.

Keys, who won her first career singles title in Eastbourne in 2014, had beaten Ostapenko in their two previous meetings. But Keys could not maintain her undefeated streak against the Latvian as she was undone by her injury despite receiving treatment at 5-2.

Ostapenko, who has won her last seven Eastbourne matches, will next face World No.36 Anhelina Kalinina for a spot in the semifinals. Kalinina took out No.16 seed Yulia Putintseva 6-3, 2-6, 6-3 in just under two hours on Wednesday evening.

Ostapenko won her lone previous pro-level meeting with Kalinina in the qualifying rounds of St. Petersburg back in 2015. Ostapenko also defeated Kalinina en route to her Junior Wimbledon singles title in 2014.