World Superbike Championship leader Max Biaggi says this year's series has been 'complicated' by the increased competitiveness of his rivals, the 2010 title winner suggesting it is becoming harder to challenge for victory.

The Italian retained his slim lead in the overall standings after round five at Donington Park, but it is an advantage that has been built on a single win at the opening round of the season and just two further podiums since then.

Indeed, though Biaggi's consistency has certainly been key to his title challenge thus far, he is determined to get back to winning ways, starting with this weekend's round at Miller Motorsports Park in the United States.

"The race in the USA is always a special round because it's different than the classic structure of the European rounds," the Aprilia rider said. "I like this track. It's very technical and the fact that we have always had good results here attests to that.

"This year things have become complicated. There are more contenders for the podium and staying up front has become more and more difficult. We have the potential to do it, if we get off on the right foot straight away."

Biaggi, who is five points ahead of Kawasaki's Tom Sykes in the overall standings, is now the only rider to have scored in each race this season.