Reigning champion Jelena Jankovic beat the rain and Aleksandra Krunic to become the first player through to the quarter-finals of the Hong Kong Open.

The seventh seed prevailed 6-4 6-3 in an all-Serbian encounter on a day when the weather brought the rest of the schedule to a halt.

World number one Angelique Kerber was locked in a tense battle with Louisa Chirico when their match was postponed in the decider.

All looked to be going to plan for the German, who was the runner-up in Hong Kong last year, when she took the first set 6-2, but a two-hour rain delay followed as she trailed 5-3 in the second.

Chirico did not let the interruption have an adverse impact, returning to wrap up the second set before proceedings were ended for the day with Kerber 2-1 up and with a break point in hand.

Daria Gavrilova, seeded eighth, will resume her contest against Katerina Siniakova on Thursday with the eighth seed leading 6-2 1-0.

Venus Williams and Alize Cornet did not make it onto court for their encounter.