However, Karatsev has had an impressive tournament and the semi-final will be the first time he has faced Djokovic.
“He impressed me, impressed a lot of people,” Djokovic added.
“His movement, his firepower from the baseline. Flat backhand, Russian school, great backhand. Looks to run around.
“Also hits some good forehands, dictates the play. He’s here for a reason, and I congratulate him for great success.
“It’s his first semi-final of a Grand Slam, so for him it’s the biggest success he has had so far.