Argentina launched their title defence with Lionel Messi scoring a hat-trick in a 3-0 win over Algeria.
They play Austria on Monday in Texas with the knockout rounds already in view, but Scaloni sounded a word of warning to any Argentina fans expecting it to be a walkover.
"What we see in this World Cup is that there is no such thing as an easy game," said Scaloni, who masterminded Argentina to the title in Qatar in 2022.
"(Even if) the group phase has always been historically (tricky), I would say this World Cup is a little bit more because there are more matches.
"The group phase has always been difficult to everyone, and the conditions, the heat and the match stops constantly.
"So that means that that might help the team that is theoretically weaker because they have time to recover."
Argentina were stunned 2-1 by Saudi Arabia in Qatar in the group stage, before going on to lift the title.
This is the biggest-ever World Cup, with 48 teams, and there are three-minute drinks breaks in each half of games this time.
Scaloni said that effectively divided matches into "four quarters".
The heat will at least not be a factor at the home of the Dallas Cowboys on Monday because it has a roof.
There will still be hydration breaks.
Midfielder Enzo Fernandez agreed that the World Cup in North America is tighter than in 2022.
"I believe that the play is becoming more and more level," said the Chelsea star.
"And it is also more competitive this time compared to Qatar.
"This is my opinion, maybe I am mistaken, but I believe today, many national teams are causing a surprise here."
World Cup 2026
The 2026 World Cup will be held from June 11th to July 19th in the United States, Canada and Mexico. The tournament will feature 48 national teams and will be played in 16 modern stadiums.
Match schedule and times | Group tables | England at the World Cup | Scotland at the World Cup | Team rosters at the World Cup | How to watch the World Cup | Predictions and odds | Which teams could be considered dark horses?