Papamoa's Van Duin looked like she would finish the fight in the first round when she had an armbar strapped in tight but Bell managed to escape.
"I thought it was going to come off but she just kept fighting and fighting," Van Duin said.
Van Duin was signed to Invicta in February last year but had to wait for a match-up given the women's featherweight division is rather thin.
She was slated to meet Charmaine Tweet (6-5) at Invicta FC 10 in December but the bout was scrapped only days before the event as a medical issue sidelined Tweet.
The Immortal was asked who she would like to meet next and Van Duin called for a bout with champion Cristiane 'Cyborg' Justino (13-1, 1 NC).
There's a chance that title shot may come at Invicta FC 13 in Las Vegas in July.