Novak Djokovic has described Feliciano Lopez as "very strong" ahead of their meeting in the quarter-finals of the US Open.
The world number one has never lost to the Spaniard, who is through to the last eight at Flushing Meadows for the first time in his career.
The Serbian told reporters: "I'm going to play Feliciano Lopez now who is also Spanish but doesn't possess the typical Spanish style, from the back of the court. He comes in and slices, he is physically very strong, big serve. Hopefully I can be ready for that one."
Djokovic has won the event in New York just once before, claiming the 2011 title.
