Aussie Troy Bayliss has returned to the World Superbike winners' circle at Assen after a sensational centimetre-perfect victory over in-form Briton James Toseland.

The second 22-lap bout at the Dutch circuit eventually boiled down to a man-on-man shootout between the duo, just as it had been at Phillip Island's race two earlier this year when Toseland scored the honours.

But this time Bayliss' nerves were more rock solid after Toseland ran too deep heading into the final chicane, allowing the Aussie to get better drive on the exit and earn victory by just nine thousandths of a second.

It was Bayliss' 36th World Superbike win, and again denied Toseland his first-ever double victory after he had prevailed in race one.

"It was an incredible race and there was lots of action," said Bayliss. "I take my hat off to James (Toseland), he's riding stronger and is getting more and more confident all the time."

"We were both over the limit in those last few laps, I was trying to cover my lines, slowing down in some corners and speeding up, and James was doing the same. At the last chicane the win could have been anybody's!"

Bayliss' stirring victory on his factory Ducati was vital after he faded in the last six laps of race one and finished fourth.

"I'm happy to take a win in race two but I'm also very frustrated because in the first race I thought I could possibly have taken a win," said Bayliss. "We just made a mistake and didn't use the hard front tyre, but then we did use it in the second race and the last three laps I was really struggling again. We have to put our heads together and work a bit on the setting because you just can't ride like that all the time."

Despite losing out to Bayliss in race two, Honda-backed Toseland increased his championship lead from 13 to 32pts (196 to 164) at Assen, with Suzuki's Max Biaggi still holding onto second from new lap record holder Noriyuki Haga (Yamaha, 144pts), who was battling for the lead in race two before being felled with an electrical problem.

"I have mixed feelings today," said Toseland. "I am gutted that I couldn't get the double win for the team at their home race. I was pushing so hard out there but Troy Bayliss is a tough man to beat and he just wasn't going to let that go. I made a mistake on that last chicane and went too deep on the brakes, and he just got past me. Fair play to the man ­ that was an incredible race."

"Anyway, I have two more podiums under my belt, plus another race win and I am still leading the standings so I can't really complain. I'm going to keep trying though ­ I want to get that double before the end of the year!"

Meanwhile, Bayliss (128pts) jumped to fourth in the standings at the expense of desperately unlucky countryman Troy Corser (YZF-R1, 114pts), who was running third in race one before a radiator hose clip broke on the penultimate lap, causing fluid to spay all over his rear tyre.

The end result was always going to be nasty, with the dual world champion high-siding at a fast section of the 4.555km circuit.

"I can't believe that such a small part can do that - it shouldn't have happened," said a disconsolate Corser. "That just put me out of serious contention for race two. I have a very sore left hip which has been X-rayed and they say nothing is broken. I am going to get further checks tomorrow as I can't believe how sore it is. Everything else feels okay at the moment, we will see."

In front of 70,000 spectators, Corser still finished a highly respectable fourth in race two, one spot behind Biaggi, although the retirements of Haga (technical), Ruben Xaus (Ducati, crash)) and Italian Lorenzo Lanzi (Ducati, crash) helped his cause.

In race one, Corser was in the thick of an early multi-bike freight train before the leading pack was whittled back to just Toseland and Bayliss.

However, the Australian's race would soon unravel with the aforementioned front tyre problem ­ he went from second to fifth in the space of three laps -- with Haga slotting in behind Toseland until the chequered flag. Xaus was third, while Bayliss was gifted fourth after Corser's unceremonious fluid-assisted exit.

In a day of higher than usual attrition, Honda-backed Aussie Karl Muggeridge failed to finish either race with mechanical glitches, while his teammate Josh Brookes didn't see out the first instalment before returning to finish 13th in the second.

In World Supersport, Turkey's Kenan Sofuoglu (Honda CBR600RR) led home Australian Andrew Pitt (CBR600RR) for the second successive time. Frenchman Fabien Foret (Kawasaki ZX-6RR) was third in the 21-lapper.

Newcastle's Broc Parkes (Yamaha YZF-R6) crashed out of second position on the penultimate lap, continuing a dreadful run of outs for Yamaha's World Supersport equip.

Parkes' teammate Kevin Curtain was not even on the grid at Assen because of injury, with Melbourne's Steve Martin taking his place and finishing a hard-fought 10th after a bad start.

Sofuoglu's fourth win of the season ­ and his second in a row at Assen -- has extended his title lead to a remarkable 53pts (120 to 67) over Foret, followed by Katsuaki Fujiwara (CBR600RR, 43pts), who crashed out in the opening lap at Assen.

Pitt (40pts) is now the leading Australian in fourth position, despite just competing on only two of the five rounds.