Novak Djokovic has conceded that he was defeated by the better player during his fourth-round exit at the Sony Open in Miami to Tommy Haas earlier today.

Germany's Haas had not defeated someone ranked number one in the world since 1999, but he managed to overcome Djokovic 6-2 6-4 to book his place in the last eight of the competition.

Reflecting on his defeat, Djokovic admitted that his opponent produced "great tactics".

"I congratulate him. He definitely made great tactics. He used the serve well and he moved around the court really well. He was better," said the Serbian.

"I definitely hoped and believed that I could come back. I was fighting. I was trying all the way up to the last ball. There are days where you just don't feel good on the court. Nothing really goes your way. This is one of those days. But all the credit to him for making me play this bad."

Djokovic will next compete for his nation against the United States in the quarter-finals of the Davis Cup.