Swiss champion Roger Federer said fatherhood would not affect his fervor for tennis as he eagerly awaits the birth of his first child in summer.
Federer is gearing up for Miami masters and will open against US player Kevin Kim at the weekend.
"I'm very excited, you know, so is (longtime girlfriend) Mirka. We're looking forward to see how it's going to impact our lives," said the Swiss second seed
"I'm excited to see how much longer I can play. I've got a very energy-saving game, a relaxed playing style. I already have done so many things and achieved so many great records. ... I'm just adding (it) up, you know, which is scary to some degree, even for me, you know."
The 13-time Grand Slam champion said that after training for only two sessions at Crandon Park following his Tuesday arrival in the wake of a semi-final defeat by Andy Murray at Indian Wells, he is once again suited to the courts at the venue where he won titles in 2005-06.
"I've got one more hour tomorrow, and then off we go. It's a decent amount of time to get ready. There are more of the gusty winds over Miami, and it's more humid," he said. "But it's not been bad, so it's actually been pretty easy to adapt."
Kim, ranked 107th, advanced into the second round as French opponent Michael Llodra quit with an adductor and abdominal muscle injury, losing 6-3.
In other results, Spain's Oscar Hernandez defeated Croatian veteran Ivan Ljubicic 6-4, 6-4 while former Australian Open finalist Marcos Baghdatis beat Ernests Gulbis of Latvia 6-2, 6-2.
Germans had a poor start with a pair of losses. Canadian Frank Dancevic ousted Philipp Kohlschreiber 6-4, 7-6 (7-2) while unknown Mikhail Kukushkin of Kazakstan upset Florida-based Tommy Haas 6-4, 6-4.
In women's opening play, Australian Samantha Stosur advanced when Swede Sofia Arvidsson quit injured to hand over a 6-1, 2-0 win, and Czech Lucie Safarova put out Briton Anne Keothavong 6-4, 7-5.
Federer said he still has numerous goals in tennis, including for his child to someday see him play while his career is still active.
"I'm excited to go for my sixth Wimbledon and my sixth US Open," he said as he went through his current to-do list on court. "It's fascinating and motivating at the same time. That's why I work extremely hard in the off season and make sure I'm in great shape. I'm a professional, but I like to have fun off court.
"And because I have the right balance, I think I'm going to be in the game for a long time."