The 24-year-old Australian does not appear the most physical midfield presence but revealed that aggression is part of his game he has been working on this season.
Johnson explained: “That is what Dave [Rennie] and the rest of the coaching staff have instilled this year, a bit of brutality.
“So going into games I’ve got three words I try to think of, and that’s: opportunity, brutality and accuracy. So it’s about getting the work-rate around the park and I think it has gone alright so far.
“We’re six weeks in and Dave is still trying to get his messages across, and we’ve just got to respond and play at a high pace.”
Johnson admitted that he had steeled himself for the Bloemfontein trip, which saw Glasgow emerge from a fierce and enthralling battle with a fine 29-26 win.
“They were giants,” said the 6ft centre. “I watched a Currie Cup game beforehand and thought: What am I doing here?
“But you’ve just got to put you head in some dark places sometimes and have a crack.”
Things don’t get any easier this weekend as Glasgow head to Sandy Park to open their European Champions Cup Pool 3 campaign against English champions Exeter.
“They’re Aviva Premiership champions from last season so they are going to play with a real intent, but we’ve just got to go out there and match them – even beat them – in the first 20 and continue on,” said Johnson.
“This is our first opportunity in Europe this season and everyone is buzzing for it. It’s going to be a big week, so we go out there with the opportunity, and the brutality in the tackle area, and the accuracy in our attack.
“We have concentrated on what we need to do in attack, and we’ll look at them more throughout the week and come to a gameplan which we will go down and try to execute on Saturday.”