Undefeated Colombian Irene Pacheco has retained his IBF flyweight title by unanimous 12-round decision over Mexico's Alejandro Montiel.

Judges scored the fight 118-109, 117-110 and 115-112 in favor of the 31-year-old southpaw, who now has a perfect record of 27-0.

Pacheco seized command at the start and dictated the fight until Montiel attacked in the fifth round.

Several headbutts followed, one opening a gash over the challenger's left eye.

For Montiel, it was his second world title loss after dropping a 12-round decision to then-IBF champion Mark Johnson in 1997.

Pacheco, who has now successfully defended five times, stopped Peru's Luis Cox to claim the vacant title in April of 1999.