In a rematch of their U.S. Open fourth-round meeting where Swiatek battled from a set and break down to prevail, the Pole revved up her backhand to save two breakpoints before a nervy hold as Niemeier gave her little room to work the angles.

But the top seed targeted world No.68 Niemeier's serve to grab the decisive break and with it the opening set, before surrendering serve early in the next only to hit back from 0-2 down to level at 5-5 and seal the victory.

"I knew I could get my focus up a little bit, the intensity a little bit more. So I did that," said Swiatek, who has won in the opening round of a major in 15 of her last 16 appearances.

"But, yeah, for sure, my goal for the next matches is not being in those situations and not starting the set losing a break. But it happens.

"I'm happy I was able to come back. It wasn't like I needed to really change a lot. I just needed to, as I said, have more intensity."

Swiatek, backed to stamp her authority on the women's game by winning the title vacated by the retired Ash Barty, continues her quest for a fourth major trophy when she meets Colombia's Camila Osorio in the second round.

The 21-year-old said she planned to follow the example of Barty and "be in the bubble" to cut down on social media use in a bid to shut out the noise after a period of complacency.

"I think the pre-season, and actually using more social media than during the season, not being focused on matches but doing everything I wanted to, it kind of ruined my rhythm a little bit," Swiatek said.

"On the other hand, you also need that time to charge up your energy. I feel right now it's a little bit harder to have this bubble and not feel all these interruptions and expectations.

"But that's my plan, to be in the bubble. I always enjoyed it. So I feel like day by day I'm going to be able to be in the bubble even more."