By Jake Donovan

The September 11 edition of Premier Boxing Champions (PBC) on Spike TV averaged 581,000 viewers over the course of the two-hour telecast, down roughly 15% from its previous live episode but still right around the series' overall average.

Headlining the card—which aired live from Ricoh Coliseum in Toronto, Canada—World light heavyweight champion Adonis Stevenson scored a third-round knockout of Tommy Karpency for the sixth successful championship defense.

Opening the telecast, Errol Spence knocked out Chris van Heerde in the 8th round. The bout was billed as the toughest test to date for the unbeaten welterweight, but he tore through his fellow southpaw in similar manner to each of his previous 17 pro opponents.

The ratings dropped off from the 679,000 viewership average turned in from the August 14 show, one that included the thrilling cruiserweight clash that saw Krzysztof Glowacki rise from the deck to knock out long-reigning champion Marco Huck in 11 rounds. Many have hailed the bout as the leading contender for Fight of the Year.

Stevenson (27-1, 22KOs) has now fought twice this year on either free TV or regional cable. His previous ring appearance came in April, when he headlined the inaugural installment of PBC on CBS, where he averaged 1.4 million viewers for his 12-round win over Sakio Bika in Quebec City, Canada. Stevenson has held the light heavyweight championship for more than two years, dating back to his one-punch 1st round knockout of Chad Dawson to lift the crown in June '13.

Spence (18-0, 15KOs) made his PBC debut in June, appearing on the televised undercard of the June 20 NBC show that was topped by Shawn Porter's 12-round decision win over Adrien Broner. In supporting capacity, Spence knocked out Phil Lo Greco in three rounds.

The next installment of PBC on Spike TV will air October 16, live from Chicago, Illinois. Top-rated light heavyweight contender and local favorite Andrzej Fonfara faces former light heavyweight champion Nathan Cleverly in the main event, while Kohei Kono puts his super flyweight title on the line versus former three-division champ Koki Kameda, who seeks to become the first fighter ever from Japan to claim titles in four weight classes.

Jake Donovan is the managing editor of

Twitter:  @JakeNDaBox 

Facebook Page:  JakeBScene