Serena Williams has opened up on how her pursuit of perfection can lead to unrealistic expectations, both in tennis and as a mother.

The American great hammered Daria Gavrilova 6-1 6-2 in her Cincinnati Masters opener on Monday in what was her first match since she suffered the worst defeat of her career to Johanna Konta in San Jose earlier this month.

Williams withdrew from the Rogers Cup following that loss, citing "personal reasons", and last week shared an Instagram post revealing her difficulty with postpartum emotions.

The 23-time major champion, who gave birth to her first child in September, went into further depth following her win over Gavrilova with a candid answer to the difficulties of juggling her professional career with being a parent.

"I've been through a lot of stuff in my life, but I've never been through this: having a baby and dealing with the emotions, and the ups and downs and the fears. And the excitement, quite frankly," she said.

"I just love talking about it because I feel like a lot of people have those same emotions and they don't have the same platform that I have. And mostly I want women out there to know that if I'm going through it, and I know you're going through it, then we're in this together.

"Everyone, no matter who we are, always has the same feelings.

"It can be overwhelming, and I tend to be a perfectionist, and I like to do things at a standard that is maybe unrealistic, and that includes being a mum.

"It's hard. Every day is a struggle for me just in terms of being regular and letting go and realising that I'm not going to be a perfectionist at this.

"I'm going to make mistakes and that's okay, because everyone makes mistakes. It's still something that I'm learning."