Australian top seed Ashleigh Barty and British number one Johanna Konta eased to first round victories at the Nature Valley Open in Nottingham on Tuesday as they prepare for next month's Wimbledon.
Defending champion Donna Vekic, of Croatia, earned a hard-fought win over British wild card Gabriella Taylor 7-5, 5-7, 7-6(3).
"That was a tough match -- I knew she was going to play well because she's already had a few matches on grass," Vekic, the sixth seed, said.
"It was my first match so I was struggling a little bit to find some rhythm, but I think winning 7-6 in the third is very good for my confidence."
Barty, a quarter-finalist at the tournament in 2016 and 2017, proved why grass was her favourite surface as she swept aside Switzerland's Stefanie Voegele 6-3 6-3 to progress to the last-16.
"It was pretty clean for a first match on grass. I'm very pleased with that," Barty said. "The beauty of grasscourt tennis is that you get better with matches, and there's no better way than to get out there and try to fix up your game."
Fourth-seed Konta, who finished runner-up to Vekic at Nottingham last year, is looking to move past an underwhelming start to the season in front of the home crowd. The 27-year-old beat Japan's Kurumi Nara 6-2 6-3 to book a second round spot.
Konta will take on compatriot Heather Watson in the last-16 while Barty faces China's Yingying Duan.
Slovakia's Magdalena Rybarikova, Japanese third seed Naomi Osaka and Romanian Mihaela Buzarnescu will play their second round matches on Wednesday.
Mertens, Bertens progress; Kontaveit out of Hertogenbosch
Belgian Elise Mertens and Kiki Bertens, of Netherlands, kicked off their Wimbledon preparations with victories in the first round of the Libema Open while defending champion Anna Kontaveit fell to a shock defeat at Hertogenbosch on Tuesday.
Estonian fourth-seed Kontaveit was stunned by qualifier Veronika Kudermetova, who is playing in her second WTA main draw event, with the 21-year-old battling to a 6-4, 7-6(4) win.
Second seed Mertens cruised to a 6-2, 6-4 win over Slovenian Polona Hercog and is on course to win her fourth title of the year after triumphs at Hobart, Lugano and Rabat.
Charleston Open winner and third seed Kiki Bertens had a tougher match against Russian Natalia Vikhlyantseva as the world number 19 earned a hard-fought 7-5 3-6 7-6(5) win over her 21-year-old opponent.
China's Zhang Shuai, who has singles ranking of 29, was the only other seeded player to exit the tournament after a 6-3, 6-3 defeat by 19-year-old Hungarian Fanny Stollar.
American Coco Vandeweghe, who won the title in 2016, beat Belarusian Aliaksandra Sasnovich in straight sets earlier in the tournament to keep her hopes of reclaiming the trophy alive.
The 26-year-old will face Arantxa Rus in the last-16 on Wednesday while Belgian sixth-seed Alison Van Uytvanck and Serbian Aleksandra Krunic will also be in action.
Tsitsipas, Tomic progress in Hertogenbosch
Barcelona Open runner-up Stefanos Tsitsipas recorded his first grasscourt victory on the ATP Tour by beating Australian John-Patrick Smith in the first round of the Libema Open at Hertogenbosch on Tuesday.
Australian Bernard Tomic, a Wimbledon quarter-finalist in 2011, is trying to reignite his career after slipping to 181st in the rankings and recorded his first victory since October 2017 with a 6-4 6-2 win over American Kevin King.
Greek fifth-seed Tsitsipas battled to a 3-6, 6-3, 6-4 victory over Smith, who replaced injured Dutchman Tallon Griekspoor in the first round clash.
The 19-year-old, who is 37th in the ATP singles rankings, will face Istanbul Open runner-up Malek Jaziri in the second round after the Tunisian beat Max Purcell 6-2 6-3 in less than an hour.
Eighth seed Andreas Seppi suffered a shock exit after a 6-4, 6-2 defeat by American wild card Mackenzie McDonald, who will face qualifier Alex Bolt in the next stage.
Australian Matthew Ebden knocked Tim Smyczek 6-2, 6-3 to book a second round clash against defending champion Gilles Muller on Wednesday.
Tomic will face sixth-seed Robin Haase in the second round while Spain's Fernando Verdasco takes on Russian Daniil Medvedev.