The Paraguayan, who is a one-time winner on Tour, posted a third round 70 to reach nine-under-par for 54 holes over the Tiburon Course at Carlton Resort in Naples.
The world No 48, who made four birdies and a brace of bogeys on day three, said: ???I played pretty well today. Super consistent. I hit a lot of fairways and I hit a lot of greens.??
???I made some good putts out there. So I???m looking forward to the final round.
???I???m aware of what???s going on. I like to know where I stand.?? Like I said before, I just have to keep playing my game and trust my game, and hope that it???s good enough to win out here.???
Her nearest challengers are American Morgan Pressel and Carlota Ciganda of Spain who carded rounds of 70 and 71 respectively.
Germany???s Sandra Gal is a further stroke adrift, while young Kiwi Lydia Ko is four off the pace.
The British challenge is currently being led by Scottish veteran Catriona Matthew who tees off on Sunday six strokes behind following rounds of 75-68-70.
World No 1 Korean Inbee Park is 11 strokes off the lead.