Gielnik made her Matildas debut in 2012 when she was 20 but with Australia's strong attacking prowess which featured the likes of Sam Kerr, Kyah Simon, Caitlin Foord and Lisa De Vanna, it was hard to get a foothold in the squad.

She missed out on the 2015 World Cup squad after changes to the coaching staff but a determine Gielnik wasn't going to give up.

In 2016 she found herself back in the green and gold after a superb season for her then club Brisbane Roar put her on Alen Stajcic's map for the Matildas Olympic qualifying squad. 

The Matildas would go on to be undefeated in the qualification tournament while Gielnik also scored a goal. 

However, it was a heartbreaking moment when Gielnik just missed out on the Rio Olympics squad. 

"I think the biggest challenge by far that stood out to me the most was shyly missing out of on the Olympics, just missed out by one there," she said.

"I think that was the most devastation I've felt in my career.

"I knew that feeling and I never wanted to have it again so I think that left a big desire in my heart."

The 27-year-old has been flourishing in the Matildas and has been a regular member of the team since missing out on that Olympic team.

However, since her return to Melbourne, there has been more confidence in her playing ability. 

Gielnik played a major role in Victory lifting the Premiership in the past W-League season with her pace and eye for goal. 

She spoke to The Women's Game in November last year about her desire to play in the World Cup and she said no words would be able to describe that feeling. 

"It's almost like a life achievement, I've given so much to this game for such a long time now that it's almost like the icing on cake but once again the priority with that is to get the ticket and two to be in the best possible form and shape for the team to have the chance to take that World Cup home," Gielnik said. 

Hearing whether or not she would make the Matildas 2019 World Cup squad, she was hoping for the good news.

"You're making my heart skip a beat, I don't know if this is going to be a good phone call or a bad one," Geilnik said.

"I've missed out on a World Cup and Olympics so I'm hoping third time's the charm.

"Hopefully you're about to give me some good news."

But the news she had been waiting for finally came...she was going to the World Cup. 

"This is amazing. I am crying, but it's a good cry," Gielnik said.

"I'm going to the World Cup."

Gielnik Facetimed her mum and dad to let them know the news. However, she was still crying at that point.

Her mum answered and she went white thinking she wasn't going.

"I told her the news and the tune changed quickly so it was good spirits and it was nice to see how proud they were of me," Gielnik said.