When Williams sat down at her computer in the morning she was merely hoping to find an email from Hockey Australia informing her she was picked in the Australian Jillaroos under-21 side.

To her shock the email read she was one of four rookies named to debut in the four-Test series against South Korea starting on Wednesday in Perth.

‘‘I found out at 11 o’clock today,’’ Williams told the  Newcastle Herald on Wednesday night.

‘‘I didn’t expect it at all because the younger team got announced as well.

‘‘Then I saw my name in the older team and I was like, ‘Oh my god, really.’ ‘‘Now that I’m in, I’m going to give it all I’ve got so I’m in it for a while.’’

If Williams takes the pitch at  Perth Hockey Stadium on Wednesday, she will become the first Novocastrian to represent the Hockeyroos since Redhead midfielder Alison Bruce was axed from the team in January 2011.

Hockeyroos coach Adam Commens called up Williams and Edwina Bone (ACT), Jane Claxton (South Australia) and Brooke Peris (Northern Territory) after injuries ruled out Casey Eastham and Jordyn Holzberger, while Emily Hurtz is in Europe.

“Both Brooke and Mariah have done well in the juniors and with three of our forward line unavailable it presents us with the opportunity to give them a taste of playing senior international hockey in front of a home crowd,’’ Commens said.

Williams’s selection followed a stellar performance over the past fortnight for NSW at the Australian under-21 titles in Darwin.

Despite a calf injury, she scored a goal in all seven games she played.

‘‘I actually missed three games because I tore my calf muscle, so I didn’t think I would play for the rest of the tournament after the second game,’’ she said. ‘‘Then I came back with two round games to go and the semis and the final, and just missing those three games made me want to run, run, run.’’

Williams plans to move to the Australian Institute of Sport’s hockey base in Perth after she finishes her HSC at Hunter Sports High this year and has earmarked the Commonwealth Games in Glasgow next year as her primary goal.

The Teralba-based striker has long been a hockey star on the rise.

Since moving from Parkes with her family four years ago she has become one of the leading players in Newcastle Women’s Premier League Hockey with the Souths club.

While Hockeyroos selection was a surprise for Williams, an ecstatic Souths coach Scott New said he expected 2013 to be her breakthrough season.

‘‘In the last 12 months she really blossomed as a player,’’ New said.

‘‘She’s an unbelievably talented player and unbelievably driven to succeed, so I always thought it would happen some time this year.’’

New said he was constantly impressed by her commitment to the sport.

 Williams regularly spent an hour at training practising the same drill over and over to perfect it.