Tenerife Ladies Open top seed Elina Svitolina has been forced to wait for the conclusion of her WTA Tour match against Maria Camila Osorio Serrano because of bad light.

Ukranian world No.6 Svitolina took the first set 7-5 before play was called off.

Russian Varvara Gracheva pulled of an upset as she knocked out Spain's third seed Sara Sorribes Tormo to progress 6-4 5-7 7-6 (7-4) after a contest which lasted three-and-a-half hours.

Italian fourth seed Camila Giorgi advanced after she beat qualifier Aliona Bolsova in three sets 7-6 (7-4) 3-6 6-4.

Fifth-seeded Viktorija Golubic is out after losing 6-3 6-4 to Arantxa Rus while Croatian qualifier Donna Vekic is through to the second round with a 6-1 6-4 win over American eighth seed Alison Riske.

Denmark's Clara Tauson, the seventh seed, beat Heather Watson 6-4 2-6 7-6 (8-6) to inflict a sixth consecutive loss on the British player.

Frenchwoman Alize Cornet beat Swiss qualifier Stefanie Voegele in straight sets, while there were also first-round wins for Mayar Sherif, Danka Kovinic, Saisai Zheng and Greet Minnen.