After being found in space 25m out with no defenders in sight, Johnson took the foot off the pedal and cantered into the open goal - unaware that Saints defender Shane Savage was hunting him.
Johnson should have just kicked the goal but by deliberately taking his time, it allowed Savage to make the tackle and force a behind.
Watch the stuff-up below:
Oh no, Stevie J! He's made a meal of this! #AFLSaintsCats http://t.co/DafHM0Suhb
— AFL (@AFL) August 22, 2015