The weekend take of the Disney and Marvel Studios’ sequel should push it past the record held by James Cameron’s epic of $2.7897bn (£2.23bn).
Marvel chief Kevin Feige hailed the achievement at Comic-Con in San Diego on Saturday, although it was still officially $500,000 short at the time.
Disney boss Alan Horn said fans had taken the film to “historic heights”.
Avengers: Endgame has not just been a success at the box office, it has also drawn widespread critical acclaim. When it was released, it spawned descriptions such as glorious, irresistible, intensely satisfying and masterful.
On Friday, Avengers: Endgame’s global gross was $2.7892bn, half a million dollars short of Avatar. But its weekend take was always likely to push it through the barrier. Last weekend it raked in $2.8m across the world.
The figures are not adjusted for inflation and Avatar would still be ahead it they were.
Avengers: Endgame already had other achievements. Including the biggest global opening of all time at $1.22bn when it was released in April. Therefore breaking the record of 2018’s Avengers: Infinity War.
An Avengers: Endgame re-release with added footage at the end of June, and the recent release of Spider-Man: Far from Home, have helped give Endgame a box-office kick.