''Hero'' opens at No. 1
The action thriller earns $17.8 million, making it the second No. 1 foreign-language movie this year
Jet Li's ''Hero'' will prevail
The martial-arts epic will be only the second foreign-language film to top the box office this year
''Exorcist'' had a bad beginning despite being No. 1
But the prequel fared better than comedies ''Without a Paddle'' and ''Princess Diaries 2''