Rain spoiled the party on the opening day's play at the Sydney International but it couldn't dampen the smile on the face of defending champion Angelique Kerber on Monday.

Kerber had a first-round bye but dropped into Olympic Park to re-acquaint herself with a tournament she says has become her go-to to kick off the season.

Back for more: Kerber back in Sydney to defend her title. Credit:AAP

"I really love this tournament," the German second seed said. "You have a really strong field here with really top players and to have a lot of matches before going to Melbourne [Australian Open] and then finding your confidence.

"And enjoying Sydney as well a little bit before going then to the busy Melbourne, it's always, for me, a good start of the year."