The Serbian set up the clash with Fish after semi-final opponent Jo Wilfried-Tsonga retired while trailing Djokovic 6-4 3-0.
Djokovic recorded a straight sets 6-3 6-1 victory over Fish in Miami in April but the 24-year-old expects a tougher challenge this time around.
"Conditions will be different because in Miami the bounce is bigger," said Djokovic.
"It's important when you play a player like Mardy to hold you composure, be patient and wait for your chance on his service games.
"I know he's going to come to the net. I know he's going to take his chances. He's always played like that."
Djokovic has won all six meetings between the two players.