China's Li Na has booked her place in round three of the Sony Ericsson Open in Miami, Florida, after she saw off the challenge of Hungary's Melinda Czink in straight sets.
In a tough opening set, Czink drew first blood when she broke her opponent's serve on her way to a 4-2 lead.
However, the world number eight hit back instantly as she took two service games from the world number 124.
Despite a further break from the plucky Czink, Li Na grabbed a vital third service break before she served out the set 7-5.
It was far more straightforward for China's number one in the second as she ground out two breaks of serve to claim the set 6-2.
