The home team Kudla did not have much to oppose Djokovic, in the match that was over in just over two hours. Djokovic sails on in the tournament and meets Stan Wawrinka from Switzerland in the next round.

- This was a big improvement over the last match, says Djokovic.

Even ten-ranked Madison Keys from the United States is on to the sixteenth in the tennis tournament, after defeating compatriot Sofia Kenin, ranked 20th.

The final result was written 6-3, 7-5. Keys was not feeling well, and lost the game in the second set, as she needed to control heart rate and blood pressure.

-I didn't feel 100 percent, but I'm glad I managed to get through two (sets). It would have been much harder if I had to drive one to set, Keys said after the game.

Meet Svitolina

Keys is a stable grand slam player, and has reached at least quarterfinals in five of the last eight major competitions.

In the next round she will meet Ukrainian Elina Svitolina, ranked fifth. She also went ahead by defeating a compatriot, 19-year-old Dajana Jastremska, by 6-2, 6-0.

-I was very even from the baseline and I served very well when I had to. I think my experience played a role, Svitolina said.

Earlier in the tournament, Jastremska beat out Swedish jump Rebecca Peterson.