Top seed Belinda Bencic survived a significant scare to triumph on her return from a back injury at the WTA Rosmalen Grass Court Championships.
The beaten finalist in 's-Hertogenbosch last year, world number eight Bencic made her first appearance since April against Belgium's Alison Van Uytvanck on Tuesday and breezed through the opening set.
However, Van Uytvanck - also making an injury comeback - roared into a 4-0 lead on her way to taking the second, before forcing a tie-break in the decider.
Bencic held her nerve to eventually prevail 6-2 4-6 7-6 (7-3) and will now face Varvara Lepchenko, who led Polona Hercog 6-4 4-0 when the Slovenian retired.
"I'm just very happy to be back on the court again, without pain," said Bencic. "I was very happy today: nothing hurt, and even if I lose this match, I'm just really happy to be back on the court and fight for every point."
The second, third and fourth seeds enjoyed more comfortable first-round matches, Jelena Jankovic, Kristina Mladenovic and Jelena Ostapenko winning in straight sets against Katerina Siniakova, Yaroslava Shvedova and Jovana Jaksic respectively.
Eighth seed Anna-Lena Friedsam was unable to progress, though, as she went down 6-3 7-5 to Viktorija Golubic.
Risa Ozaki will meet Golubic in a battle of two qualifiers after beating Kirsten Flipkens 6-4 6-2, while there were also wins for Evgeniya Rodina, Kateryna Kozlova, Richel Hogenkamp, Aleksandra Krunic and Nao Hibino.