Amir Khan remains the frontrunner to fight Floyd Mayweather Jr. in September, but fellow British fighter Kell Brook thinks Khan has to earn more respect before being worthy of such a fight. Brook also offered him an opportunity to earn it.

"When he [Khan] steps up he gets beat, he gets knocked out and beat. He's got no belt, he's got nothing. I'm the champion. Earn your respect by fighting me," Brook said. "I just want to get him in the ring and see who the number one is."

Brook is the undefeated IBF welterweight champion, and he's had a strong year. Brook soundly defeated Shawn Porter for the belt in 2014, but was knocked out of action for several months shortly after when he was attacked with a machete. Since returning, Brook has made it a point to be an active champion. While constantly calling for Khan, Brook has fought twice.

Brook defeated Jo Jo Dan by stoppage in March, and followed it up with a TKO victory over Frankie Gavin just two months later. With a date with Khan unlikely, Brook is already planning to defend his title again vs. the durable Brandon "Bam Bam" Rios.

Rios was impressive in his most recent fight, a one-sided knockout of rival Mike Alvarado. He said he's not only willing to fight Brook, but will go to England for him. "I'm ready as of today," Rios told ESPN.com. "I'm ready to go whenever. I've been keeping in shape. I'm ready to rock and roll."

Rios vs. Brook would be a classic clash of aggressor vs. counter-puncher, but Brook and his promoter Eddie Hearn remain disappointed that Khan has given them, and the British boxing fans, the cold shoulder.

"Everybody wants Brook against Khan but what can you do? He is waiting for Floyd Mayweather, but that fight isn't happening in September. Apparently he thinks it could happen next May. It is a waiting game and it is disappointing for the British public because Kell Brook wants to fight Amir Khan," Hearn said.