In what is billed as 'the richest game in the world of football', due to the massive sums of top division television money that are up for grabs, Mooy buried his team's fourth penalty in a shootout as they went on to topple Reading FC after the match had finished 0-0.

With Mooy pulling the strings in midfield, Huddersfield completely dominated the chances during the contest - German defender Michael Hefele should have put them in front in the opening five minutes, after the Australian had curled in an exquisite free kick - but his point blank header went wide.

A few moments later, Izzy Brown missed an open goal from close range as the game threatened to break wide open. But instead, that was the last meaningful moment in what was a dull 120 minutes of football.

Despite what became a stifling contest, the former Western Sydney Wanderers and Melbourne City star was undoubtedly one of the best on ground as every attack seemed to flow through him - with several dangerous free kicks needing just a telling touch to perhaps find their way into the Reading net.

After the final whistle, it was Hefele again who wasted a golden chance as his penalty was easily saved by Ali Al-Habsi. Reading were in the box seat before Liam Moore blasted one miles over the crossbar and Jordan Obita has his shot saved by Danny Ward. Christopher Schindler calmly converted Town's fifth and final spot kick, giving them a 4-3 win.

"I just tried to think positive because of lots of negative things come into your head, like if I miss this I'll cost the team," Mooy said.

"I didn't want to be the one who stuffed it up. They creep in but I just try and keep talking positive to myself and say you're going to put it in.

"After about the 80-minute mark you starting thinking this could go to penalties, I'm going to be definitely taking one.

"The last 30 minutes I couldn't run anymore, I was too tried."

Mooy converted his spot-kick in the second leg win over Sheffield Wednesday last week, which secured the Terriers a place in the final.

But the 26-year-old said you can "never really" prepare for the pressure-cooker of penalty shootout.

"They say the Germans don't miss and we've got a lot of Germans, maybe that's why," he said."We had that experience [at Hillsborough] and Reading didn't; maybe that helped.

"You still have to be lucky for the keeper not to guess your way. There's a bit of luck and concentration."

Mooy was delighted with The Terriers' promotion to England's top flight, describing it as one of the happiest days in his life.

"Apart from my baby's birth and getting married, this is the best day," Mooy said. "It's been a big few weeks but it's all worth it.

"It's crazy. It's just been a rollercoaster, so many ups and downs, but it's all worth it. Everything's worth it, this day.

"Lots of players don't get to play at Wembley, so coming today is something very special. But to win and get a team promoted to the Premier League and be part of it is amazing. It's unbelievable."

Mooy joined the Terriers on loan from Manchester City at the beginning of the season, and was voted into the EFL Team of the Season after stringing together a slew of quality displays under manager David Wagner. His future is uncertain; it's not known whether his parent club will recall him for next year, loan him out again or sell him (either to Huddersfield, or somewhere else).

It was the first time since 2002 that the final had gone to a shootout, and funnily enough, another Australia slotted the penultimate penalty for the winning side with Stan Lazaridis holding his nerve as Birmingham City beat Norwich City.

With AAP