Inglewood, CA (SportsNetwork.com) - Gennady Golovkin continued his savage dominance over the middleweight competition with another knockout on Saturday night.

Golovkin (33-0) polished off Willie Monroe Jr. with a sixth-round technical knockout to retain his WBC middleweight title and the WBA middleweight belt.

The 33-year-old registered his 30th knockout -- including the 20th straight stoppage -- of his impressive career. He said after the match in a postfight interview with HBO's Max Kellerman that he wanted to unify the belts, also naming such fighters as Miguel Cotto and Saul "Canelo" Alvarez as possible bouts for the near future.

Golovkin cracked Monroe with a right and dropped him in the second round, then moments later when Monroe got back to his feet, Golovkin clipped him with a sharp left for a second knockdown.

Monroe (19-2, 6 KOs) was a little more active in the fourth as he landed 33 of 80 punches in the round. He popped Golovkin with successive shots that caused the champion to pump his chest and demand more, but the challenger could not maintain that brief success.

Golovkin came out firing in the sixth and attacked Monroe from the onset. A right uppercut stunned Monroe and he eventually backed into the ropes before taking a few more punches and falling to the canvas for a third and final time. The fight was stopped 45 seconds into the round.

On the undercard, Roman Gonzalez (43-0, 37 KOs) made quick work of Edgar Sosa. Gonzalez knocked Sosa (51-9, 30 KOs) down three times in the second round to complete the TKO win and capture the WBC flyweight title.