By Nicolas Samuilov, notifight.com

Sampson Lewkowicz, adviser to pound-for-pound middleweight fighter Sergio Martinez (49-2-2, 28KOs), admits his fighter's career is at stake on September 15th, when he challenges Julio Cesar Chavez Jr. (46-01, 32KOs) for the WBC middleweight crown at the Thomas & Mack Center.

A loss for Martinez, 37-years-old, would cost the boxer his much pursued fights against Floyd Mayweather Jr., Saul Alvarez and Manny Pacquiao.

"It's a very tough fight for both. Chavez will have the weight advantage. He will go up at least ten kilos above Martinez. With that [weight] alone he has a lot in his favor. What you have for Martinez is the speed, experience and talent, against the force and weight [of Chavez]," Lewkowicz said.

"In boxing, one punch can change an entire fight, regardless of what happened up until that point. It will be a fight in which one mistake can cause the retirement of Martinez. Because if Martinez were to lose to Chavez, he would have nothing else to do in boxing. Whoever thinks that Martinez is taking this fight without respect [for Chavez] is very wrong. Because he is in the biggest fight of his life because [the fate of his career is at stake]."

Both fighters are predicting knockout victories, but Sampson expects the fight to go the distance, with Martinez getting the win by outboxing the bigger man.