Tim Tszyu came in a full pound under the junior middleweight limit Saturday afternoon for his title defense against Brian Mendoza.

Sydney’s Tszyu stepped on the scale at 153 pounds at the weigh-in for their 12-round, 154-pound title fight Sunday afternoon, which was held outdoors in Broadbeach, Australia. Albuquerque’s Mendoza officially weighed in exactly at the 154-pound limit for a championship clash Showtime will televise in the United States as the main event of a doubleheader scheduled to start Saturday night at 10:30 p.m. EDT (7:30 p.m. PDT).

Tszyu-Mendoza will also headline a Main Event on Kayo Sports pay-per-view show scheduled to start at 12 p.m. AEST on Sunday afternoon from Gold Coast Convention & Exhibition Centre in Broadbeach ($59.95).

Tszyu (23-0, 17 KOs) will make his first defense as the WBO junior middleweight champion. He was elevated from interim champion September 30 when former fully unified 154-pound champ Jermell Charlo was stripped of his WBO belt because he moved up two weight classes to challenge undisputed super middleweight champ Canelo Alvarez for his IBF, WBA, WBC and WBO 168-pound crowns at T-Mobile Arena in Las Vegas.

The 28-year-old Tszyu has stopped former WBC champ Tony Harrison (29-4-1, 21 KOs) in the ninth round and knocked out Mexican veteran Carlos Ocampo (35-3, 23 KOs) in the first round in his two bouts since his January 28 fight against Charlo was postponed and ultimately canceled because Charlo suffered two broken bones in his left hand late last December.

Mendoza (22-2, 16 KOs) produced perhaps boxing’s “Knockout of the Year” in his last fight. Down decisively on all three scorecards through six rounds of action, Mendoza caught 6-foot-6 southpaw Sebastian Fundora with a counter left hook that badly hurt Fundora.

Mendoza followed up with a right-left combination that knocked Fundora flat on his back and out early in the seventh round. The 29-year-old Mendoza won the WBC interim super welterweight title from Fundora (20-1-1, 13 KOs).

Earlier Saturday, Sam Goodman and Miguel Flores made weight for their 12-round featherweight fight.

Goodman (15-0, 7 KOs), of Albion, New South Wales, Australia, and Flores (25-4-1, 12 KOs), of Spring, Texas, officially came in at 124¾ pounds apiece. Goodman, a 122-pound contender, upset American Ra’eese Aleem (20-1, 12 KOs) by split decision in his last fight – a 12-rounder June 18 at Gold Coast Convention & Exhibition Centre.

Showtime will air Goodman-Flores as the opener of its doubleheader.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.