Tom Cruise opens a movie at No. 1, and -- voilà! -- all is right with his box-office career again.

So says conventional wisdom.

But did "Oblivion" perform all that differently than other recent Cruise films?

Let's drill down into the numbers -- and come up with a surprising answer:

* "Oblivion" scored a three-day domestic opening of $37.1 million. All things considered, that's a good number -- per BoxOfficeMojo.com stats, it's one of the biggest ever for an April opener, and it's Cruise's biggest in nearly seven years.

One thing, though: From a strict domestic perspective, "Oblivion's" opening weekend is really no more -- or less -- impressive than that of "Jack Reacher" or "Valkyrie," to name two perceived Cruise failures.

In its first frame, the reportedly $120 million "Oblivion" made back 31 percent of its price tag from stateside ticket sales. "Jack Reacher" scored 25 percent; "Valkyrie," 28 percent -- not all that far off from this past weekend's entry.

[Related: Get local showtimes and tickets for "Oblivion"]

What made "Oblivion" appear that much stronger than the earlier films (aside from the admittedly stronger numbers and the No. 1 ranking) was the fact that the sci-fi thriller had been playing overseas for more than a week. "Oblivion" couldn't be accused of making "only" $38 million if it's already grossed about $150 million worldwide.

* "Oblivion" made money because Cruise movies, meaning movies in which Cruise is in full-on Cruise form, (almost) always make money.

Domestically, "Jack Reacher" was a miss; "Knight & Day," too. And, yes, "Mission: Impossible III" seemed to fall to the so-called curse of the threequel. But on the whole, Cruise movies have kept on keeping on, even after what is widely considered to be their star's shark-jumping moment: the 2005 leap on Oprah Winfrey's couch.

Post-Oprah, however, Cruise has gone onto release the two biggest-grossing Cruise movies of his career, "War of the Worlds" (his top domestic performer) and "Mission: Impossible--Ghost Protocol" (his top worldwide performer).

As for the non-Cruise Cruise movies? Same as always. They've been sketchy at the box office, from "Far and Away" to "Lions for Lambs," from "Magnolia" to "Rock of Ages."

And besides, if you're looking for the line of demarcation in Cruise's career it's the dawn of the 21st century, not the jump on Oprah's couch. Sixty percent of Cruise's top 20 domestic hits of all-time were released prior to 2000.

* The bottom line: Cruise's career was neither as bad off as you may have thought it was, pre-"Oblivion," nor as back on track as you may think it is, post-"Oblivion."

Sometimes, a No. 1 film is just a No. 1 film.

See Tom Cruise in an "Oblivion" featurette...