Luke McDonald was consuming a chocolate milk drink in the North Melbourne change rooms when his night took a dramatic turn.

As one of the travelling emergencies for the semi-final against the Swans, the 20-year-old had just watched his teammates run out onto the ground for the first warm up and assumed he would be watching the game from the stands.

He was wrong.

Robbie Tarrant tweaked a groin with his first kick and was forced to head back to the rooms for treatment.

“Taz (Tarrant) walks in and I’m like ‘what’s he doing here’”, McDonald told NMFC.com.au.

“Then Commie (Steve Saunders) comes in and he’s like ‘Luke, warm up’… I thought he was joking.”

Tarrant was unable to take his place in the side and McDonald was called up with just minutes to spare.

“You sort of prepare to play but you never think you’re going to play,” he admitted.

In an amazing turn of events, the young defender found himself in the thick of the action and was finally able to chalk up a significant career achievement in the process.

“I started doing a few run-throughs. I didn’t think he (Tarrant) was actually going to pull out and then he pulled out and the next minute I’m out there and kicking my first goal.”

McDonald’s first major in the AFL came in his 37th game.

“I couldn’t believe it really. I’m still that excited about it,” he said.

“It was unbelievable. I was just so excited. Finally, the monkey’s off the back.

“10 minutes before the game I was sitting down drinking choccie milk, now this is happened so it’s an unbelievable feeling.”