The former Miss World, who is currently shooting in LA for her maiden American show, said was pitted against Kangana for her film "Mary Kom".
"I hate losing. But if I had to take a back seat to anyone this year it would be U #KanganaRanaut ! Congratulations!yay Queen!#SmallTownGirls," Priyanka tweeted.
The actress also congratulated "Queen" director Vikas Bahl and "Haider" helmer Vishal Bhardwaj with whom she worked in "7 Khoon Maaf".
The movie was named the best popular film providing wholesome entertainment.
Director Omung Kumar said he was on top of the world.
"I'm feeling on top of the world, debut film and a national award... Couldn't have asked for more. I want to thank Mary Kom for giving me her fabulous story. I want to thank Sanjay sir (Sanjay Leela Bhansali), PC (Priyanka Chopra) and the entire cast and crew for making such a fabulous movie with me," Kumar said.
"Yippee to team #MaryKom @priyankachopra @OmungKumar @Vanita_ok @MangteC @OnlerK We won the National Award best film," Quadras posted on Twitter.
Released last September, the Manipur-set drama also starred Darshan Kumaar and Sunil Thapa in prominent roles.
