Carson, CA - Gennady Golovkin extended his knockout streak to 18 consecutive matches, this time stopping Marco Antonio Rubio in the second round.

Rubio failed to make weight Friday, which ultimately cost him his interim WBC belt and a shot at Golovkin's WBA middleweight belt, but the 34-year-old was no match for his opponent from Kazakhstan.

Golovkin (31-0, 28 KOs) landed a right uppercut and then delivered a left hook that connected to the top of Rubio's (59-6-1, 51 KOs) head. Rubio fell to the canvas and was counted out at 1:19 of the second round.

Because Golovkin now holds Rubio's WBC interim belt, he is slated to fight the winner of the Miguel Cotto bout versus Canelo Alvarez.

On the undercard, Nicholas Walters scored a sixth-round knockout to Nonito Donaire to win the WBA featherweight title.

With 30 seconds left in the third round, Walters (25-0, 21 KOs), who was in his first championship bout, landed a solid right uppercut that put Donaire (33-3, 21 KOs) on the canvas for the first time in his career.

By the time the fourth round began, Donaire's right eye was starting to swell from a cut that he sustained.

With the sixth round about to come to a close, Donaire missed with a left hook, and Walters countered by landing a right to the top of the head. Donaire, who was making his first title defense, was officially counted out with one second remaining in the round.