LOS ANGELES (AFP) — Tall American southpaw Sebastian Fundora stunned previously unbeaten Australian Tim Tszyu to unify two world junior middleweight boxing titles in a bout that became a bloody spectacle.

After a strong start, Tszyu struck his head accidentally on the left elbow of the 6-foot-5 challenger in the second round, a deep bleeding gash opened above his forehand turning the Aussie's face crimson round after round, blood blinding him for much of the fight.

Judges scored the fight 116-112 and 115-113 for Fundora and 116-112 for Tszyu, giving the US fighter a split decision victory for Tszyu's World Boxing Organization junior middleweight title and the vacant World Boxing Council (WBC) crown.

"I'm just happy Tim Tszyu gave me the opportunity and I made it a dream come true," Fundora said.

"The way I won my belt, it was an honor to share my belt and make history with him."

Fundora, 26, improved to 21-1 with one draw in becoming the tallest 154-pound champion in history while Tszyu fell to 24-1.

Tszyu, a 29-year-old from Sydney and the son of former light-welterweight world champion Kostya Tszyu, admitted the blood that turned his face crimson most of the night impacted his effort.

"I couldn't see," Tszyu said.

"But all credit belongs to the man who won."