(CNN) -- Manny Pacquiao and Floyd Mayweather Jr. have turned to mediation in a last-ditch bid to save their March 13 super-fight in Las Vegas.
The proposed bout has been thrown into considerable doubt after a row over drugs testing escalated with Pacquiao taking legal action against Mayweather and his connections.
But representatives of the two fighters are due to meet on Tuesday with retired federal judge Daniel Weinstein, who solved a dispute relating to promotional rights for Pacquiao three years ago.
Pacquiao's promoter and Top Rank chairman Bob Arum has every faith in Weinstein's abilities.
"This guy was successful resolving our nutty problem before and hopefully he can be successful this time. He's a guy who is a big fight fan and loves the sport, and I found him last time to be a delight to deal with. Everybody did," he told ESPN.com.
Filipino hero Pacquiao has been infuriated by the insistence of Mayweather and his team at Golden Boy Promotions that both fighters submit to Olympic-style blood testing in the buildup to their pay-per-view extravaganza.
This guy was successful resolving our nutty problem before and hopefully he can be successful this time.
Pacquiao filed a lawsuit in a federal court in Las Vegas last week for defamation against Mayweather and others for allegedly claiming he had used performance-enhancing drugs.
It was another twist in a saga which has threatened to derail what many boxing experts predict will be the richest fight in boxing history, with projections of each fighter earning $40 million.
The bout at welterweight appeared to be virtually set after other issues around the cut of the purse for each fighter were settled, but then the drug-testing row erupted over the Christmas period.
Pacquiao became a five-weight world champion after his WBO welterweight title win over Miguel Cotto in November, while the unbeaten Mayweather returned from a 21-month retirement to beat Mexican Juan Manuel Marquez in September.