When it comes to building with tiny Lego bricks, who’d have thought that tackling height was the biggest challenge on the game board.

But on Sunday night’s episode of Lego Masters on Channel 9, a single challenge proved that stacking blocks on top of one another is the toughest task to appear on the program.

In the first challenge, Hamish Blake tested contestants' abilities with a task that nine-year-olds around the country would scoff at.

“Build the tallest building possible,” said Blake to the eager contestants. The prize? An advantage for a future build that could ultimately lead to a prize pool of $100k.

But it wasn’t as straightforward as it seemed, as a hurdle was thrown into the mix sending gasps throughout The Brick Pitt.

Build as high as you possibly can without any assistance from a stool or any other device to give contestants any form of extra height.

“You are stool-less for this challenge. I repeat – no stools,” warned Blake.

“You have two hours. Two hours to go as high as you can. Tallest tower wins.”

With no aesthetics being judged, no story, and no design features to follow – contestants had to beat the 4-metre stick and build the tallest structure in the room.

Some took the challenge in their stride, others got caught out with “flimsy” structures that put everyone on edge.

“This is intense,” Blake said as the timer ticked away.

“This is the fastest build we’ve ever had on Lego Masters and also the highest build. A double record day.”

High school sweethearts Tim and Dannii had a strong start but best friends Andrew and Damian were not planning to let them win.

But despite the mates beating the stick, in the end it was childhood friends Jay and Stani who showed the rest of the room just how well they could beat the stick, with a final structure “well over four metres”.

“It’s closer to five metres,” said Blake in awe.

“That is just unbelievable.”

Lego Masters airs on Channel 9 each Sunday at 7 pm and Monday at 7.30pm.