When Black Panther first came on tracking two weeks ago, NRG forecast a domestic opening of $125 million. By last week, that number had shot up to $150 million-plus.

Directed by Ryan Coogler, Black Panther is unprecedented in being a big-budget studio tentpole featuring a virtually all-black cast. In the film, Chadwick Boseman stars as T'Challa/Black Panther alongside Lupita Nyong'o, Michael B. Jordan, Daniel Kaluuya, Letitia Wright, Winston Duke, Angela Bassett, Forest Whitaker and Andy Serkis.

If NRG is right, Black Panther could potentially notch one of the top five or six domestic openings ever for a superhero film, not accounting for inflation. Of course, tracking often misses the mark. Either way, the pic appears headed for greatness in North America.

The big unknown is how Black Panther will fare overseas, where Hollywood films with a black cast are perceived to face challenges. Disney insiders expect Black Panther to open in the $75 millionto $115 million range. The tentpole rolls out in about 70 percent of the international marketplace this week; major territories where it doesn't open until later include Russia (Feb. 22), Japan (March 1) and China (March 9).

The critically acclaimed movie currently boasts a stellar 97 percent score on Rotten Tomatoes, the best of any title in the Marvel Cinematic Universe (that could change by opening day).

The roster of top superhero openings in North America is led by The Avengers (2012) with $207.4 million, followed by Avengers: Age of Ultron (2015) with $191.3 million, Captain America: Civil War (2016) with $179.1 million, Iron Man 3 (2013) with $174.1 million — all from Marvel — and Batman v. Superman: Dawn of Justice (2016) with $166 million and The Dark Knight Rises (2012) with $160.9 million, not accounting for inflation.

Ryan Reynolds' Deadpool, which currently holds the record for top February opening, took in $152.2 million over the four-day Presidents Day weekend in 2016.