It was among the greatest moments of the 21-year-old’s career as she plundered the Belmont course for two-under-par 290, including a competition record five-under 68 on Wednesday.

Hillier led defending champion Breanna Elliott, of Yarrawonga, by nine shots heading into the final round.

Only a monumental blunder would have wrested the title from the Joondalup member and none was forthcoming as she shot two-under 75, which included two birdies and four bogeys.

Elliott (297) shot 73 to finish second, ahead of Tilly Poulsen, of Melbourne’s Kingston Heath, who carded 76 for 301.

Carly Beck, of the Australian, finished a shot away in fourth place. New Zealand’s Sarah Bradley finished fifth on 303.

‘‘I’m feeling awesome right now,’’ Hillier said.

‘‘I just kept it together today, kept the pressure on and finished solid.

‘‘I’m really proud of myself.

‘‘I still had to finish it off and Bree was playing really solid today. She shot even and was making a lot of birdies out there.

‘‘I was really happy I kept the lead really big.’’

Elliott led the field after day one courtesy of a four-under 69. Hillier was third, four shots behind.

But from there the tournament belonged to the bubbly right-hander as she carded 68-74-75 to close out her first 72-hole senior event.

Hillier’s short game was the feature of her performance.

Each day she completed the round with under 30 putts. ‘‘That’s what I’ve been working on with my coaches back home, putting together four consistent rounds,’’ Hillier said.

‘‘I was solid all week and I’m just so happy to do that. It gives me great confidence for next week. Hopefully I’ll turn pro next year, so it’s a good finish for Belmont.’’

Hillier flew to Melbourne last night to prepare for the Australian Women’s Amateur on Tuesday at Woodlands and Huntingdale, in Melbourne.