THIS weekend is a big one, both in world and Australian boxing, with the Pacquaio v Mosley and Sylvester v Geale title fights on Sunday.

In the early hours of Sunday morning, Daniel Geale's big moment comes when he challenges Germany's IBF world middleweight champion Sebastian Sylvester in Nuebrandenbarg, while in the early afternoon, Shane Mosley takes on Manny Pacquaio in a WBO welterweight title match in Las Vegas.

Geale, 30, with a 24-1, 15ko record, has improved with every appearance since his step-out fight against Anthony Mundine, in which he lost his IBO belt by the narrowest of margins in May, 2009.

Only 10 boxers have previously held the coveted IBF 72.57kg/11st 6lb crown and Geale is looking to join fistic luminaries like Marvin Hagler, Michael Nunn, James Toney, Roy Jones and Bernard Hopkins.

Sylvester, also 30, who has a record of 34-3-1, 16ko, has made three defences of the title he won in September, 2009.

He was extended to a draw by former light middleweight champ Roman Karmazin last June.

Karmazin was then halted by Geale in the final seconds of a one-sided affair in October.

Geale goes in with a six-inch (15cm) height advantage on paper and is 5-1 in fights going 12 rounds.

Sylvester, a former amateur international who was knocked out in a round in his pro debut, is almost twice as experienced over the journey and has a 9-1-1 record in fights that have gone 12 rounds.

But, as I said last week, I can't see Geale losing.

Geale's pin-point accuracy and angle work figure to be too much for the German. Main Event Pay Per View coverage starts at 4am.

Shane Mosley (46-6-1, 39ko) is given a reasonable chance to upset superstar Manny Pacquaio (52-3-2, 38ko) when they battle for the Filipino's WBO welterweight (66.68kg/10st 7lb) belt.

Mosley is the first African-American foe Pacquaio has faced and there are people who think the speed, dazzling combinations and cracking right hand of Mosley might give Manny serious problems, despite the fact that “Sugar Shane” is six months shy of hitting 40 years of age and was unimpressive in his last start, a draw against former world champion Sergio Mora.

Prior to the Mora bout, Mosley lost badly on points to unbeaten Floyd Mayweather but had Mayweather in trouble in round two.

All great champions have one last great night left, but that might have come when Mosley destroyed tough-as-concrete Mexican Antonio Margarito in nine brutal rounds in January, 2009. Margarito went the journey but took a horrible beating from Pacquaio last November.

Pacquaio, 32, is the first left-hander Mosley has faced since 2007 and it no doubt shapes to be a hard fight for Mosley.

But if the Californian can turn back the clock once more, there might be several surprised faces ringside at the end of the night.

It looms as a tremendous battle. Main Event PPV begins at 11.30am.