Former lightweight titlist Brandon Rios has lost two fights in a row: a close decision to Mike Alvarado in their interim junior welterweight rematch, a 2013 fight of the year candidate, followed by a one-sided pasting by Manny Pacquiao in a welterweight fight.

After the loss to Pacquiao in November in Macau, Rios tested positive for a banned stimulant (which didn’t help, because Pacquiao won basically every round in an utterly lopsided fight).

A third loss in a row would be a death knell to Rios’ career in terms of six-figure paydays on major televised cards.

Having served a suspension for the failed drug test, Rios is now aiming to re-establish himself while also making some noise at welterweight by taking on rugged Diego Chaves on Aug. 2 (HBO) at The Cosmopolitan in Las Vegas.

“I am looking forward to getting back in the ring. I feel like it’s been a long time since I fought. I miss boxing,” Rios said Wednesday at his media day at trainer Robert Garcia’s gym in Oxnard, California. “I know that a lot of people think I am done but believe I am far from being finished. Pacquiao was a very difficult fight for me and I just felt I could have done better, but he was just too fast.”

He won’t have to worry about Argentina’s Chaves having the kind of speed Pacquiao has. Chaves (23-1, 19 KOs) is similar to Rios (31-2-1, 23 KOs) in that he is more likely to stand and brawl than give angles like Pacquiao can.

Chaves showed enormous toughness -- and a fan-friendly style -- last July when he lost his interim welterweight belt by 10th-round knockout to Keith Thurman in San Antonio, Texas, in an excellent fight.

“Chaves is a tough fighter and I expect a good, hard fight and one the fans will enjoy,” Rios said. “I know I could have fought an easier opponent but I want to show everyone what I am still capable of doing against a top-level guy.”

Rios knows it’s a pivotal fight.

“It's do or die for me and I will do what I have to do to win this fight,” Rios said.