MELBOURNE, Australia (AFP) — Rafael Nadal said he was grateful to his wife Mery for travelling to Australia with their baby boy, admitting he was not sure he could cope without them for a month.

The Spanish great became a father for the first time in October and is playing at his first Grand Slam since, leaving home in late December for the United Cup in Sydney before heading to Melbourne Park.

Speaking at the Australian Open, where he won in the first round Monday, the defending champion said being a dad had not affected his competitive "feelings or motivation."

"Only could create a negative impact if I was here for one month and they were not able to be with me," he added.

"You don't know how you are going to react, you know?"

"I don't know my feeling if the baby's not here with me for one month. I don't know if after three weeks I miss him, and I lost a little bit the focus."