Teslas launch of its futuristic Cybertruck pickup suffered a setback when its armoured glass windows shattered but it was the overall look of the car that worried Wall Street on Friday, sending the companys shares lower.

In the much-anticipated unveiling to cheering fans late on Thursday, Tesla boss Elon Musk had taken a stab at the design, power and durability of mainstream trucks, only to be shaken when his boast about his new vehicles windows backfired.

To show off the robust design of the new pickup, Musk asked von Holzhausen to take a sledgehammer to the side of the vehicle, whose exterior will be made from the same stainless steel used in the Starship rocket developed by Musks SpaceX aerospace company.

Maybe that was a little too hard

The crowd cheered when the hammer bounced off the surface without leaving a mark.

But the supposedly tough windows shattered with just one hit.

Oh my f*****g God, well, maybe that was a little too hard, Musk said, when his head of design, Franz von Holzhausen, cracked the drivers side window with a metal ball in a series of pre-planned tests for the crowd.

He allowed von Holzhausen another throw to the rear passenger window, only to see that crack, as well.

It didnt go through, so thats a plus side, Musk said, adding: Room for improvement.