Alstare Suzuki’s Leon Haslam will lead the Superbike World Championship into this weekend’s fourth round of the 2010 series at Assen in the Netherlands, currently leading the 13-round title in his maiden year on the factory Suzuki team.

Haslam finished on the podium in both races last year on a privateer Honda, with the two races won by American Ben Spies and Japanese favourite Noriyuki Haga.

Ducati Xerox rider Haga, the lap record holder at the historic Dutch circuit, broke through for his first win of the year in race two at Valencia’s most recent round of the series, and he’s fully aware that he’ll have to maintain those exacting standards so that Haslam doesn’t extend his championship lead at Valencia.

Haslam is currently on 123 points, 18 points ahead of Aprilia’s four-time 250GP World Champion Max Biaggi, while Spanish privateer Althea Ducati rider Carlos Checa is third in the standings on 80 points.

Season 2010 has already produced four race winners, only one less than what there was in the entire 2009 season.

Other contenders to watch for this weekend include Yamaha teammates Cal Crutchlow and James Toseland, Ten Kate Honda’s Jonathan Rea, and Aprilia revelation Leon Camier.

Spies and Haga’s victories at Assen last season snapped an arresting Australian streak at Assen, with Queenslander Chris Vermeulen’s commanding run in 2004-2005 followed by four Troy Bayliss victories from 2006-2008.

As reported in Breaking News earlier this week, Vermeulen will finally make his World Superbike return this weekend, the 28-year-old forced out since injuring his right knee in the season opener at Phillip Island, but after a recent arthroscope he’s ready to renew acquaintances with his factory Kawasaki.

“My knee is improving every day since I had keyhole surgery and I have a good feeling in most of its range,” said Vermeulen. “The difficult part now is getting enough bend but also strength and stability in my knee because I don’t want to turn up to just ride around.

“I really enjoy racing at Assen and have had successful results there in both superbikes and in MotoGP, and I also get a lot of support there because of my Dutch heritage. I therefore hope that I can put on a good show as I join the team once again.”

As far as championship honours are concerned, three-time Assen winner at Vermeulen knows that 2010 is now beyond him as he looks ahead to an all-out attack on a brand new Kawasaki in 2011, but the same can’t be said for his rapidly-improving compatriot Troy Corser.

The dual world champion just missed out on scoring BMW’s first podium in the last round at Valencia, and he’s now right in the thick of a logjam battling for sixth spot in the championship.

Corser has never won a race at Assen despite having 38 WSBK wins to his credit, but with recent improvements in acceleration and top speed on the factory BMW S 1000 RR, he now has a good chance to break his drought.

“In the early years of my career we used to race on the old Assen circuit, which I liked a lot,” Corser commented. “It was an old-school kind of track, the sort you used to get a lot of in the 1970s – flat, quick and with a lot of long, sweeping corners.

“The character of the circuit has been retained, despite a series of modifications, but it has lost some of its appeal for the riders. That’s not the case for the fans, though; this is still a great event and the atmosphere’s fantastic. At Assen you have to take a big risk to be really ultra-fast, and that doesn’t necessarily suit my riding style. I’m just taking each race as it comes.”

Following a long convalescence, Newcastle’s Broc Parkes will also make his return at Assen with the ECHO CRS Honda team after breaking his tibia in the pre-season, ensuring a full Aussie presence for the first time this year as Port Macquarie’s Andrew Pitt will be the fourth Australian in action on another BMW.

In World Supersport, Kawasaki’s Joan Lascorz has 65 points to Ten Kate Honda’s Kenan Sofuoglu’s 61, while Eugene Laverty has experienced of a rough patch after a brilliant start to the year at Phillip Island and sits third in the series on 41 points.

Laverty prevailed in a high-octane five-way world supersport battle at Assen last year, with the quintet separated by less than two seconds after 21 pulsating laps.