Bernabe Concepcion had his moment, knocking down Juan Manuel Lopez at the end of the first round Saturday in San Juan, Puerto Rico. The Filipino was stopped the following round. Photo / Tom Casino-Showtime

Juan Manuel Lopez’s promoters have big plans for the undefeated featherweight titleholder. They believe the southpaw boxer-puncher, who is already wildly popular in his native Puerto Rico, is a future star.

Lopez, who successfully defended his title with a second-round knockout of Bernabe Concepcion on Saturday in San Juan, will probably one day earn a pound-for-pound ranking and pack 20,000 fans inside of Madison Square Garden.

For now, however, Lopez is one of the most-exciting fighters in the sport.

The victory over Concepcion is irrefutable proof of Lopez’s ability to thrill fans.

The Showtime-televised bout featured four knockdowns in five minutes and 37 seconds of action. It wasn’t an exhibition in the Sweet Science. Only one jab was landed during the entire fight. Lopez landed it. The 27-year-old two-division beltholder edged Concepcion in other key areas, mainly power punches (27 to 10) and knockdowns (three to one).

Lopez (29-0, 26 knockouts) staggered Concepcion into the ropes with a counter left one minute into the first round and later dropped the Filipino banger. However, as the Puerto Rican closed in for the kill, Concepcion (28-4-1, 15 KOs) lashed out with a left hook that floored Lopez with 15 seconds left in the round.

Lopez put Concepcion down with another straight left just seconds into the second round. The Manny Pacquiao prot├®g├® got up and appeared to momentarily hurt Lopez with a right hand to the body with a minute left in the round, but Lopez landed a series of right hooks that rocked Concepcion back on his heels. An accurate left that landed while the game challenger was reeling deposited him on the canvas in a corner.

Concepcion struggled to his unsteady feet, prompting referee Luis Pabon to wisely wave the bout off at 2:37 of the round.

Lopez is already scheduled to face veteran Rafael Marquez on Sept. 18 in Las Vegas. If the former junior featherweight champ was watching the Concepcion fight, he probably received a boost of confidence watching Lopez hit the deck at the end of the first round.

That’s OK. Fans received a boost of adrenaline during that moment and those same fans will have more interest in the Marquez fight.

Lopez didn’t make a big deal of the knockdown, the first of his career.

“I have to learn not to be overconfident,” he said during his post-fight interview.

Some will question Lopez’s potential, particularly in the 126-pound division, where dangerous fighters such as Chris John, Celestino Caballero and promotional stablemate Yuriorkis Gamboa call home.

It’s a fair question given the fact that Concepcion is a fringe contender, and Rogers Mtagwa, who repeatedly rocked Lopez and nearly had him out in the final round of their slugfest last October, is considered a journeyman.

However, anyone who doubts that a seemingly vulnerable fighter can break into the pound-for-pound top 10 and pack arenas should take a look at the resume’s of Lopez’s countrymen, Felix Trinidad and Miguel Cotto.

Trinidad was dropped in fights with Anthony Stephens, Yory Boy Campas, Oba Carr, David Reid, Fernando Vargas and Bernard Hopkins.

Cotto was rocked in fights with DeMarcus Corley and Zab Judah. He was dropped in bouts with Ricardo Torres and Manny Pacquiao.

Like Trinidad and Cotto, Lopez possesses heavy hands, tight technique and an offensive style, but his vulnerability, as it was with his fellow Puerto Rican heroes, is the main thing that thrills the fans.