According to Showbuzz Daily, the replay for Canelo vs. GGG shown on September 23 averaged 726,000 viewers, peaking at 840,000 viewers during the closing moments of the fight. The fight ended in a controversial split draw with each fighter winning on one card while one card scoring the fight a 114-114 draw.
The replay was just the lead-in to HBO's live broadcast of the WBA lightweight title fight between Jorge Linares and Luke Campbell, which drew a much lower viewership. Linares vs. Campbell averaged 687,000 viewers while peaking at 726,000 viewers.
The average viewership for both of those fights were marginally lower than HBO's prior television card, which was main evented by Roman "Chocolatito" Gonzalez vs. Srisaket Sor Rungvisai. The super flyweight title rematch from September 9 averaged 796,000 viewers while peaking at 835,000 viewers.
Linares defeated Campbell by split decision to retain his title while setting a potential lightweight unification bout between him and WBC champion Mikey Garcia.
In other boxing ratings news, ESPN's broadcast of Top Rank Boxing from September 22, headlined by Oscar Valdez vs. Genesis Servania, averaged 706,000 viewers, far lower than the 1.2 million viewers ESPN's broadcast of the Terence Crawford vs. Julius Indongo from late August drew and only slightly lower than the August 5 broadcast of Vasyl Lomachenko vs. Miguel Marriaga (728,000 viewers).