In a crunch Rugby Championship clash at Kings Park in Durban, kicking off at 17:10 on Saturday, the Boks will face Los Pumas with the outcome set to massively impact the title race.
Brown says the Argentines will put them under serious pressure on home soil.
"It was a good performance against the All Blacks, but Argentina are a different team, playing pretty good rugby – they've beaten the All Blacks already and beat Australia," said Brown.
"So the message to our guys is, if we don't prepare as well as we can, and don't pitch up and be as physical and dominant as possible, we're going to be put under pressure, so getting our game right is the massive part for us this week."
This will be South Africa’s final home fixture of the season, and Brown stresses the importance of executing their game plan from start to finish.
"We've shown good patches of rugby this year, but I don't think we've put 80 minutes together, so my goal is to get us to perform for 80 minutes and execute all the opportunities that we're producing, and try and really put teams away," he added.
"So even though, like I said, we were good against the All Blacks, our first half was still riddled with errors, and we've just got to be better in those situations."