The hosts captured the first game on Wednesday by 40 runs but England, the reigning 50-over World Cup and Twenty20 World champions, rebounded to take the second match on Thursday by 13 runs and square the series.
Coach Sherwin Campbell said the team was upbeat ahead of the crucial match at Warner Park, and were confident they could undermine England.
“We are getting better and better with every game. The more we play the better we are becoming and this is pleasing,” the former West Indies vice-captain said.
“We now have the final ODI on Saturday (today) and I believe we have a realistic chance of beating England and winning the series. There is self-belief in this team and a lot of confidence.”
On Thursday, the Windies women put up a tremendous fight but still failed to secure an unbeatable 2-0 lead in the series.
England made 232 for six off their 50 overs and in reply, the Windies girls were always in the hunt but fell for 219 off 48.5 overs.
Campbell said he was pleased with his players despite the loss.
“We played brilliantly on Wednesday to beat the world champions. We showed we have the ability to perform at this level and to dominate in all three departments,” said the former West Indies opener who played 52 Tests between 1995 and 2002.
“Today (Thursday) we could not complete the job but I thought we played well. There was a bit of panic there at the end and I felt our inexperience at this level is what beat us.”
West Indies – Merissa Aguilleira (Captain), Anisa Mohammed (Vice Captain), Shemaine Campbelle, Britney Cooper, Shanel Daley, Deandra Dottin, Cordel Jack, Stacy Ann King, Pamela Lavine, Chadean Nation, Amanda Samaroo, Tremayne Smartt, Shakera Selman, Stafanie Taylor.
England – Charlotte Edwards (Captain), Caroline Atkins, Tamsin Beaumont, Katherine Brunt, Holly Colvin, Lydia Greenway, Isa Guha, Jenny Gunn, Danielle Hazell, Laura Marsh, Beth Morgan, Ebony Rainford-Brent, Nicky Shaw, Anya Shrubsole.