American Paul Malignaggi stopped previously undefeated Ukrainian Vyacheslav Senchenko in the ninth round Sunday to take the WBA welterweight title Sunday.

The referee stepped in to halt the fight at 1:10 in the ninth after Malignaggi pounded the left side of Senchenko's face until his eye closed.

The 31-year-old Malignaggi, the former IBF junior welterweight champion, improved to 31-4 with his seventh career knockout. The 35-year-old Senchenko dropped to 32-1 in front of a sparse home crowd at Donbass Arena.

Senchenko, who hasn't fought outside Ukraine for more than five years, struggled from the start with Malignaggi's speed. The New Yorker was able to move in and out, firing off rapid punches while avoiding the slower, taller Ukrainian's strikes.

Malignaggi started fast from the first bell, firing jabs and dodging quickly to stay away from the Ukrainian, who was making his fourth defense.

Senchenko snapped back Malignaggi's head with two stiff jabs in the third, but the challenger continued to pepper him with punches.

The champion landed another big left jab in the fourth, but his face was already showing the marks from his opponent's relentless work, particularly around his left eye.

Senchenko increased his work rate in the sixth and seventh as his eye began to close. But he couldn't find anything to trouble Malignaggi, who continued to punish his opponent's cut and bruised left cheek.

The champion's eye was swollen shut by the end of the seventh. He pushed forward in the eighth and ninth, as referee Steve Smoger warned that the end was near.

Smoger finally ended the bout in the ninth when Malignaggi caught Senchenko with a right that the exasperated Ukrainian couldn't see coming.