BUENOS AIRES, Argentina (January 21, 2017) -- With her best round of the week Mexico's Isabella Fierro kept her name atop the South American Women's Amateur leaderboard with one round remaining. After beginning the day in a tie for first, Fierro was able to shake free with a 5-under 67 that saw her reach 10-under and open up her biggest lead of the week at four-strokes.

Playing at Martindale Country Club Fierro got off to a strong start with a 1st hole birdie as she set the stage for a 1-under 35 front side. However, it was heading for home where Fierro did most of her work.

Fierro rolled in a birdie on No. 10 and then four in a row from Nos. 14-17 that brought her to 11-under. A bogey did follow on the closing hole but not even a final hole dropped stroke could rub the shine off of the stellar round from Fierro.

Second round co-leader Delfina Acosta of Argentina is in second place at 6-under and she will be the closest competitor to Fierro when the final round begins on Sunday. The Miami senior shot a 1-under 71 on Saturday with three birdies and two bogeys. Her birdies came on the 5th, 10th and 15th holes.

Argentine's Ela Anacona and Magdalena Simmermacher will begin the fourth round in a tie for third at 4-under while two-time defending champion Sofia Garcia of Paraguay is fifth at 1-under.

American's Julia Potter and Meghan Stasi ended the first 54-holes of the week tied for 10th at 2-over. Stasi shot up the leaderboard with a 4-under 68 in the third round that included five birdies, an eagle and two bogeys. The eagle came on the par-5 17th and it followed a birdie on No. 16. Stasi also rolled in three consecutive birdies from Nos. 2-4.

ENTRIES OPEN: Entries are now open for 2024 U.S. Mid-Amateur Championship

Charlie Woods shoots 9-over 81 in U.S. Open Local Qualifier

15-year-old Miles Russell climbing the leaderboard on Sunday

Meet the five amateurs teeing it up at The 2024 Masters

Miles Russell shatters records in Korn Ferry Tour and professional golf debut