United beat the Melbourne Victory 5-4 in a penalty shootout in at Geelong's Simonds Stadium after there were no goals in regulation or in half an hour of extra-time.

United will now travel to Perth to play Perth Glory in this weekend's grand final after the Western Australians defeated sydney FC in the other semi-final.

Goalkeeper Chantel Jones was the hero in the end, saying she knew she would stop at least one of the penalties after both teams went a perfect four from four to start.

"I knew I had to stay focused even if I missed the first few and guessed wrong," Jones said.

"All the penalty kicks they had taken had gone to my left, so I was going left and we'll see what happens. I knew I just needed one because I knew my team would step up."

Fletcher did just that, the midfielder slotting her kick into the bottom left corner of the net past Victory's impressive goalkeeper Brianna Davey.

"This is my contribution," Fletcher said. "I wanted to help get the girls to the finals and this is what I had to do.

"I wanted to take that responsibility on my shoulders. I was able to sneak it by her and get the girls into the final."

The irony is Fletcher won't be allowed to play in this weekend's grand final.

With the three full-time import spots filled by fellow Americans Jones, Lori Lindsey and Stephanie Ochs, Fletcher is the team's designated guest player who is allowed seven games for the season.

Saturday's semi-final was number seven.

She started her contract a week early, helping United to a crucial 1-0 win against the Victory in round seven.

"Soccer's a team sport and sometimes your number's called and sometimes it's not," Fletcher said.

"I'd love to be out there with the girls but I've got no doubt in my mind that they're going to go out there and do everything they can to win the thing.

"My job next week will be to cheer them on."

United had plenty of chances to score, starting in the opening five minutes when Sykes couldn't get a foot on a great ball from Michelle Heyman.

Matildas striker Heyman got herself in great positions, continually troubling the Victory defence but unable to capitalise.

Heyman went within a whisker of scoring the winner in the 88th minute but her header bounced off the side of the goalpost.

She had another chance with the last kick of the game but put her shot straight into the waiting arms of Davey.