Argentina are tough up front anyway but put them in front of fervent home support and they are like an overdone steak.
The All Blacks encountered that on their last trip to South America in 2006, when they battled to a 25-19 victory against a side who sniffed a chance of a first ever win over New Zealand.
Mealamu was in the All Blacks squad for that match but didn't play, but it's a game that left a lasting impression on a player who has now donned the black jersey in 96 tests since his debut against Wales in 2002.
"I remember quite vividly how tough the game was and, hearing the chanting of the crowd, it was an amazing atmosphere for us," he said.
"We love the passion over here. We love the way the supporters support their team. There's going to be quite a bit of noise out there and it's going to be something we will have to try to deal with. We are not used to that sort of noise in our stadiums back home."
It will make a good start imperative. Mealamu said they hoped to do that to nullify the effect of the crowd but the Pumas will be equally motivated to keep the home support in it.
They did a good job of that against South Africa a month ago only to concede late points and allow the Springboks back into the match to clinch a 16-16 draw. It's a result that didn't go unnoticed in the All Blacks camp.
"The way they have played, they have showed they deserve to be in this competition," wing Ben Smith said. "They are a pretty strong rugby force. I think the All Blacks have always had respect for Argentina. They are playing as we thought they would."
Sunday's game is the sort of match the All Blacks would love to have a couple of enforcers for. The era of dirty play is largely over - although South African prop Dean Greyling did his best to rekindle it with his disgraceful forearm to Richie McCaw's head - but there is still a place for tough players to exert their power and influence.
Two players who used to fill this role were Brad Thorn and Jerome Kaino and Mealamu admitted this was one reason the All Black pack had so far failed to achieve dominance in the Rugby Championship.
"They left a big whole when they left," he said. "They're guys who had a lot of experience in the jersey and their presence on the field has been huge.
"It's a new pack finding our way at the moment."