By Mark Lamport-Stokes

LOS ANGELES (Reuters) - Manny Pacquiao is regarded as one of the greatest boxers ever but says he will not be taking his opponent lightly when he faces World Boxing Organization welterweight champion Jessie Vargas next week.

Seven months after defeating Timothy Bradley in his much trumpeted farewell to the sport, the Filipino southpaw will return to the ring on Nov. 5 when he faces American Vargas at the Thomas & Mack Center in Las Vegas.

"I do not underestimate Jessie Vargas," Pacquiao, 37, told reporters after beginning his training camp in Los Angeles this week under the watchful eye of his Hall of Famer trainer Freddie Roach at the Wild Card Boxing Club.

"He is a good strong champion. Every opponent gets my full attention and respect. I respect Jessie and that is why I trained hard. This is the most important fight because it will determine the direction of my boxing career."

The 27-year-old Vargas (27-1) beat fellow American Sadam Ali in March to claim the WBO welterweight crown and has won 10 of his bouts via a knockout or stoppage, with his only defeat coming via a points loss to Bradley in June 2015.

"I need to win convincingly," said Pacquiao. "We have three different plans for Jessie Vargas, but my first concern is for the fans; that the people who are going to watch the fight will be happy and satisfied."

Pacquiao, an eight-division world champion, is excited by the prospect of adding another title to his bulging career resume, and his first since he was elected to the Philippines' senate in May.

"I am fighting for history," said the Filipino, who is renowned for his lightning hand and foot speed and has compiled a 58-6-2 career record in the ring. "I was the first sitting congressman to win a world title.

"For this one, it is not enough to be the first sitting senator to fight for a world title. I want to be the first senator to become world champion. For me, that would be quite an accomplishment.

"I want to prove that I am still one of the best pound-for-pound fighters. I am not done with boxing. I will continue to keep fighting as long as I love boxing and boxing still loves me. I do not feel old. I feel like I am still 27."

(Editing by Frank Pingue)