Erakovic and Parra Santonja were seeking their first match win that didn't come via retirement, while sixth-seeded Americans Kops-Jones and Spears are eight-time WTA titlists and are fourth on the Road To Singapore leaderboard.
But Erakovic served out both tight sets at 5-4 for the 6-4, 6-4 triumph.
"We were as aggressive as we could be because we know that Raquel and Abi are super aggressive," Erakovic said. "We really needed to take it to them and we tried to do that most of the match. We had our ups and downs but I think we played a solid match and hopefully we can keep improving."
"It was a great match," Parra Santonja said. "We had only played one tournament before together. I thought we would make a good team because we have good groundstrokes and serves. I think she's a very nice person and that makes it more comfortable for me to be in sync with her."
Among Tuesday's matches is a clash featuring No.5 seeds Cara Black and Sania Mirza and reigning Miami champions Martina Hingis and Sabine Lisicki. Hingis was the champion here in doubles in 1999 alongside Anna Kournikova and in singles in 2006.