Djokovic overtook Rafael Nadal as the No. 1 player by reaching the Wimbledon final. He defeated the Spaniard in four sets in the championship match to win his third Grand Slam title.
"I'm very confident and it's obvious," Djokovic said Thursday. "I mean, I have lost one match in the last seven or eight months. I'm trying to keep that confidence at a very high level."
Djokovic said Eleskovic beat him at a junior tournament years ago, and he is ready to meet him again.
"We know Eleskovic quite well, but I haven't seen him play for a long time," he said.
Reverse singles will be played on Sunday.
The winning team will face either Kazakhstan or Argentina in the semifinals.