China's Li Na has reached the fourth round of Wimbledon after a tough battle against the Czech Republic's Klara Zakopalova.

Both players were broken on their first service games, before Zakopalova managed the vital one to claim the opening set 6-4.

In the second, Li came out fighting and wrapped it up inside 25 minutes, before Zakopalova regrouped in the third.

At the start, neither player was able to hold and, despite Zakopalova having the chance to serve for the match, Li broke again late on to clinch it 8-6.

Li moves on to face Roberta Vinci in the next round.