Quentin Tarantino Calls Paul Dano the 'Weakest F***ing Actor in SAG'

Quentin Tarantino's worked with some of the biggest and baddest stars in the 'biz, but it doesn't look like he'll be collaborating with Paul Dano anytime soon ... because he just blasted one of the actor's most celebrated performances.

On Tuesday's episode of "The Bret Easton Ellis Podcast," Tarantino trashed Dano's work ... he said the 2007 flick "There Will Be Blood" would have been great without one "big giant flaw" -- you guessed it, he was talking about Dano!

If you haven't seen the flick, Dano portrays twin brothers Paul and Eli Sunday, earning a nomination for a BAFTA Award for Best Actor in a Supporting Role.

Tarantino really laid into Dano in "There Will Be Blood" ... he said his performance was "weak sauce" compared to Daniel Day-Lewis, who earned an Oscar for his work in the film.

The "Kill Bill" director said Austin Butler would have been a better choice to portray the Sunday brothers ... even though Butler was still a teenager when the movie was produced.

Tarantino questioned why Day-Lewis had to costar with the "weakest male actor in SAG" and said Dano gave a "non-entity performance" in the flick.