Pacquiao, 35, puts the belt on the line for the first time since avenging his loss to Timothy Bradley earlier this year and faces the current WBO champion at 140lbs.
Algieri won the light-welterweight strap in a surprise victory over hard-hitting Ruslan Provodnikov – ending any hopes the Russian had of sealing a fight with his former stablemate.
The 30 year-old is a snow white underdog to put another dent in Pacquiao’s record, but will earn a career-high purse of £1 million plus for his troubles.
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Pictures by Chris Farina/Top Rank