Dominguez, twice silver medal winner at World Championships, clocked nine minutes 7.32 seconds for the win. Zarudneva took the silver in 9:08.39 and Kenya's Milcah Chemos Cheywa was third in 9:08.57.
Olympic champion Gulnara Galkina of Russia finished fourth.
"This is the most important victory of my life and I hope to win a gold medal again in 2010 (at the European championships).
"I worked so hard for this. I felt very good during the whole race and I was able to control it."
Zarudneva said, "I knew it was going to be a very hard race. Mylegs were heavy but surprisingly it improved during the last meters. I am glad because I got the silver medal but I would be happier if it was gold."