By Jake Donovan

It’s been less than a week since tickets went on sale and the September 15 middleweight title fight between alphabet beltholder Julio Cesar Chavez Jr and lineal champion Sergio Martinez is already well on its way to becoming a sold-out event.

A four-city press tour was held to promote the event, with the last stop coming Tuesday afternoon in Mexico City. The session took place in the TV Azteca studios, where Zanfer Box – Chavez Jr’s co-promoter - insisted that tickets are moving along at an exceptional rate. More than 70% of the 18,000 seats already filled, with event handlers truly optimistic of a sold-out venue well before fight night.

“We sold nearly 13,000 tickets within the first 24 hours,” Fernando Beltran, who heads Zanfer, revealed on the show. “We are already sold out of $400 tickets.”

Martinez (49-2-2, 28KO) makes the fifth defense of the lineal middleweight belt he won from Kelly Pavlik more than two years ago. The Argentine southpaw heads to Vegas for just the third time in his career. One of those trips provided the lone definitive loss of his career, when was stopped by Antonio Margarito in seven rounds more than a dozen years ago.

Chavez Jr. (46-0-1, 32KO) advances his career to a level of respectability once entering the title fray last year. A vacant title win – the title Martinez was forced to give up - over Sebastian Zbik last summer marked his debut on HBO, where he has now appeared in each of his past four fights.

Both fighters will headline an HBO PPV for the first time. So far, the response has been overwhelming with praise. Shadowing the card is another event taking place two miles away on the same evening. Saul ‘Canelo’ Alvarez – Chavez Jr’s countryman and ratings rival – faces Josesito Lopez in a super welterweight bout which tops the bill for a Showtime-televised quadruple header at the MGM Grand.

Those involved in the promotion for the HBO PPV card never seemed concerned about the competition. In fact, they believe there isn’t even any competition to speak of given the importance of the fight and magnitude of the overall event.

“To tell you about September 15 – there is no owner for that date,” Beltran states. “The best combination and the best fight owns the date. That’s why we own the date on pay-per-view. There is no other fight on the date in the interest of the Mexican public.

“We’re not announcing a fight of Chavez against TBA. We already have the best two middleweights in the world facing one another.”

Jake Donovan is the Managing Editor of Boxingscene.com. Follow Jake on Twitter: @JakeNDaBox