HBO Boxing presents day-night action from two continents, highlighted by a pair world championship fights featuring two of the sport’s top pound-for-pound performers, when WORLD CHAMPIONSHIP BOXING: GENNADY GOLOVKIN VS. KELL BROOK AND ROMAN “CHOCOLATITO” GONZALEZ VS. CARLOS CUADRAS AND YOSHIHIRO KAMEGAI VS. JESUS SOTO KARASS 2 is seen SATURDAY, SEPT. 10, first at 5:30 p.m. (live ET/tape-delayed PT) from London and then at 10:00 p.m. (live ET/tape-delayed PT) from Inglewood, Cal., exclusively on HBO. The HBO Sports team will call all the action, which will be available in HDTV, closed-captioned for the hearing-impaired and presented in Spanish on HBO Latino.

Other HBO playdates: Sept. 11 (9:15 a.m.) and 12 (11:00 p.m.)

HBO2 playdates: Sept. 11 (4:15 p.m.) and 13 (midnight)

The tripleheader will also be available on HBO NOW, HBO GO and HBO On Demand.

At 5:30 p.m. (ET/PT), from The O2 in London, powerhouse Gennady Golovkin (35-0, 32 KOs), originally from Karaganda, Kazakhstan, and now training at Big Bear, Cal., defends his middleweight crown against Kell Brook (36-0, 25 KOs), from Sheffield, England, in a scheduled 12-round contest.

Seeking his 17th consecutive successful 160-pound title defense, Golovkin is drawing closer to Bernard Hopkins’ record of 20 successful middleweight title defenses. On a 22-bout knockout streak, Golovkin has compiled an extraordinary knockout-to-win ratio of 91%, and no opponent has gone the distance with him since June 2008. Trained by the highly regarded Abel Sanchez, he will be making his 11th appearance on HBO since his auspicious Sept. 2012 debut on the network.

With a 69% knockout-to-victory ratio, Brook became the British welterweight champion in 2008 and is a current world welterweight champion. Having defended his title successfully three times, he is moving up two weight classes to take on the formidable Golovkin.

At 10:00 p.m. (ET/PT), from The Forum in Inglewood, Cal., the primetime bouts kick off with Yoshihiro Kamegai (26-3-2, 23 KOs), from Tokyo, Japan, taking on Jesus Soto Karass (28-10-4, 18 KOs) of Los Moches, Mexico, who now lives in North Hollywood, Cal., in a scheduled ten-round super welterweight fight. These ring warriors fought to a split-decision draw in April and now look to settle the score in their heated rivalry.

Then, undefeated fighters Roman “Chocolatito” Gonzalez (45-0, 38 KOs), from Managua, Nicaragua, and Carlos Cuadras (35-0-1, 27 KOs), from Mexico City, Mexico, meet in a scheduled 12-round super flyweight title fight. Gonzalez has brought worldwide attention to the lower weight divisions with his speed and power, boasting an 84% knockout-to-win ratio. Cuadras, with a 75% knockout-to-win ratio, is a super flyweight champion and looks to halt Gonzalez’s quest for a world title in a fourth weight class.

The primetime presentation will also feature a replay of the Golovkin-Brook bout from earlier in the day. Immediately following all the boxing action, HBO Sports will premiere at approximately 12:45 a.m. (ET/PT) ROAD TO CANELO/SMITH, a special chronicling the path to the Sept. 17 junior middleweight pay-per-view title fight at AT&T Stadium in Arlington, Tex. between Canelo Alvarez and Liam Smith.

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All HBO boxing events are presented in HDTV. HBO viewers must have access to the HBO HDTV channel to watch HBO programming in high definition.