The champion and hometown hero proved too classy for his Argentine opponent, compelling the judges to score a unanimous decision in his favour with totals of 116-111, 116-111 and 115-112.
The 27-year-old had previously retained the belt against Miguel Beltran Jnr and Martin Honorio and improves his record to 34-2-1 while Barros, a year his junior, suffered his third career defeat.
Rene Gonzalez retained his WBA Fedelatin lightweight title over Ricardo Alvarez via split decision to bring his record to 31-5. Alvarez fell to his second loss in a close and hard-fought battle.
Local lightweight Alejandro Sanabria stopped Seiichi Okada of Japan in the eighth round on the undercard in his 25th career knockout. His record now stands at 33-1 with Okada now 16-3.