Novak Djokovic said working with coach Andy Murray still felt a bit surreal, but it offered him the opportunity to finally build a personal relationship with the Scot after their long rivalry on court.
Djokovic, a 24-times Grand Slam champion, appointed fellow former world No 1 Murray ahead of this year's Australian Open and said at the Qatar Open they would continue working together for an indefinite period.
The duo reunited during hardcourt tournaments in the United States and, after reaching the Miami Open quarterfinals on Tuesday, Djokovic said he was grateful to have Murray on board.
"We shared the same stage, so to say, and were on the tour for a very long time and know each other for 20-25 years since the junior days," Djokovic told Sky Sports.
"But obviously when you're rivals you don't interact as much and actually as we were waiting for matches to restart after the rain today we had a very interesting talk.
"I've always had tremendous respect for Andy, as a player, but now even more so as a person. He's such a nice guy and I'm really grateful he cares about me doing well on the court."
Djokovic won 25 of his 36 matches against Murray and said he was still getting used to having the Briton in his corner.
"It's still surreal that one of my biggest rivals is my coach, and he's fist-bumping and jumping around in the box," Djokovic said.
"Sometimes I pinch myself and ask myself 'is this real? Is this a dream?' but it's great.
"We're trying to get the most out of this relationship of player and coach and also to spend some quality time together. Miami has been good. We were here early, almost a week before the tournament started.
"We played some golf, we enjoyed some dinners together and we're having fun."