Ruffels carded a one-under-par 70 in more water-logged conditions to finish in a tie for 13th at five over for the championship in Houston.

It was the 20-year-old' amateur's second top-15 finish at a major this year and left Ruffels as the leading Australian at the demanding Champions Golf Club.

"It's been awesome, so much fun," Ruffels said.

"I feel like any time I can kind of mix it with the pros and know that I can compete against them, it's a great week.

"I feel like I did that this week and just gained a lot of confidence."

Ruffels was two under through five holes on Sunday before torrential rain and thunderstorms forced the suspension play.

She resumed on Monday where she left off, continuing her aggressive play with a stylish birdie-birdie finish to surge from 39th position to a share of 13th with six players, including New Zealand's former world No.1 Lydia Ko.

"Definitely you had to be mentally strong coming back from yesterday," Ruffels said.

"I knew I had kind of a roll going but I knew it was going to be tough starting out today.

"It was going to be pretty cold and I made a few bogeys early but was happy that I was able to get it back."

Ruffels, the second low amateur in the field behind only American Kaitlyn Papp, finished eight shots behind South Korean winner A Lim Kim.

With a purse of $US5.5 million ($A7.3m) on offer, Ruffels would have collected a cheque for $US96,800 ($A128,500).

But she turned it down to retain her amateur status in what has been a breakout year for a genuine rising star in the making.

In addition to sharing 15th at the ANA Inspiration, she made the final at her defence of the 2019 US Amateur title, losing on the 38th hole to American Rose Zhang.

Hannah Green was next best of the Australians who made the cut in Texas, in a tie for 40th at nine over after closing with a 75.

Minjee Lee also shot 75 to tie for 46th at 11 over, while Sue Oh finished with an 80 to round out the weekend field in 66th at +20.

Australian Associated Press