HONG KONG, SAR – Angelique Kerber will be forced to dig deep to reach the quarterfinals of the Prudential Hong Kong Tennis Open after a gutsy second-set performance from Louisa Chirico.

The World No.1 and top seed breezed through the first set, which she eventually won 6-2 after a series of unforced errors from the 20-year-old allowed the German to race into a 4-1 lead.

However, Chirico returned with renewed vigour in the second set and Kerber did not look the same after a brief rain delay. An error-strewn service game at 2-3 gave Chirico the break and she held on to her lead, only for rain to strike at 40-30 when she was serving for the set. After a lengthy delay, she held her nerve to force a decider, despite being dragged into an epic 37-shot rally.

Kerber’s out-of-sorts form continued in the first three games of the third set, which remains on serve although Chirico was set to defend a break point when the bad weather returned, forcing the postponement of play until Thursday.

Jelena Jankovic continued her defence of the tournament with a routine straight sets victory over fellow Serb Aleksandra Krunic.

Having held her own against the former World No.1, the 23-year-old faltered on serve at 4-4, with two double faults and two weak shots into the net giving Jankovic a first-set lead she did not surrender.

The two compatriots exchanged two breaks apiece at the start of the second set but, serving for a 4-3 lead, Krunic sent a wayward drop shot wide and a backhand into the net to give Jankovic the advantage. The 31-year-old made no mistake from there, holding and breaking once more to book her place in the next round.

Eighth seed Daria Gavrilova’s match with Katerina Siniakova fell victim to the rain with the Australian leading 6-2, 1-0, with a break of serve in the second set. Venus Williams’ match with Alizé Cornet was postponed due to the bad weather.