Starling Castillo was pushed to the limit in earning his latest victory.

Going ten rounds for the first time in his career, Dominican Republic’s Castillo fended off a tough challenge offered by former title challenger Juan Carlos Burgos in claiming a ten-round, unanimous decision victory.

Judges Josef Mason (98-92),  Robert Hecko (97-93) and Mike Fitzgerald (96-94) all scored in favor of Castillo in an excellent lightweight battle Sunday evening live on Fox from The Armory in Minneapolis, Minnesota.

Castillo—a training stablemate of unbeaten junior middleweight contender Sebastian Fundora—was riding high following a second-round knockout of Miguel ‘Caveman’ Contreras in their battle of unbeaten prospects just two months ago. The 25-year-old Dominican southpaw proved to be ready for the next level, with that increase in competition coming in a stiff challenge from the well-experienced Burgos. Castillo was crisp with his power shots in the opening round, needing every bit of leverage on his right uppercut and chopping left hands as Burgos—who has never been in 42 fights following Sunday’s affair—refused to back down.

A fun two-way exchange in round two saw Burgos get the better of the action. The 33-year-old Tijuana native ate a right hook and responded with a looping left hook over the top to snap back the head of Castillo.

The battle swayed back in favor of Castillo in round three, still enduring his rough moments but otherwise dictating the pace through a long jab and combination punching. Burgos was successful in cutting off the ring, though unable to beat the younger Castillo to the punch once at close quarters.

Castillo put his superior boxing skills to use in rounds four and five. Less movement was offered by the unbeaten lightweight who dug in with his right uppercut both on the inside and from long range.

Burgos punched his way back into the fight in round six. The Mexican veteran connected with left hooks to the lean body of Castillo, who took the shots well but was being outmuscled during such exchanges.

Round seven saw Burgos charge forward, maintaining a tight guard as Castillo let his hands go and responded with jabs and right hands. Castillo remained poised, taking a step back to avoid Burgos’ shots and responding with jabs and chopping left hands.

Castillo returned to boxing and moving, forcing Burgos to follow him around the ring while working primarily behind his jab. Burgos let his hands go whenever managing to get Castillo within punching range but was often outworked during such exchanges.

Burgos took his shot in the final thirty seconds, riding out several flurries from Castillo to empty his own gas tank. Castillo—who has never previously been past eight rounds—could have easily boxed his way to victory but opted to show his fighting side. Rapid fire combinations landed along the ropes, though nearly punching himself out as Burgos responded with heavy blows at fight’s close.

The win provided valuable lessons for Castillo, who improves to 16-0 (12KOs) with the points win after having scored four straight second-round knockouts.

Burgos falls to 34-6-2 (21KOs), though proving to be a tough out for the next generation. The former three-time title challenger offered a stiff challenge in an otherwise widely-scored decision in favor of Xavier Martinez just four months ago in Carson, California.

Headlining the show, Jesus Ramos (16-0, 14KOs) faces Brian Mendoza (19-1, 13KOs) in a scheduled ten-round junior middleweight contest.

Jake Donovan is a senior writer for Twitter: @JakeNDaBox