Chris Vermeulen claimed his first career pole on Saturday

Vermeulen stormed to a comprehensive victory in the opener but had to win a titanic battle with Yamaha's Noriyuki Haga to claim race two.

He is now 86 points behind Troy Corser who had two fourth-place finishes.

Reigning champion James Toseland came home ahead of Haga in race one and ended up third in the second race.

The opening race saw Vermeulen keep the chasing pack at bay after making an early break.

Toseland had a tougher time of it and had to fight off the attentions of Haga to secure second place.

The Briton was fighting for the lead in race two but a mistake allowed Vermeulen and Haga to break clear.

The lead kept changing hands before Haga looked to have made the decisive move with just four laps to go.

However, Vermeulen took the lead on the penultimate lap and was able to hold on by just a single bike length.

Dutch Grand Prix race one result:
1 Chris Vermeulen (Aus) Honda 33 mins 36.026 secs
2 James Toseland (GB) Ducati 33:39.425
3 Noriyuki Haga (Jpn) Yamaha 33:40.905
4 Troy Corser (Aus) Suzuki 33:42.844
5 Andrew Pitt (Aus) Yamaha 33:46.104
6 Yukio Kagayama (Jpn) Suzuki 33:48.555
7 Lorenzo Lanzi (It) Ducati 33:48.690
8 Max Neukirchner (Ger) Honda 33:56.624
9 Karl Muggeridge (Aus) Honda 33:56.901
10 Pierfrancesco Chili (It) Honda 34:03.720

Dutch Grand Prix race two result:
1 Chris Vermeulen (Aus) Honda 33:34.053
2 Noriyuki Haga (Jpn) Yamaha 33:34.138
3 James Toseland (GB) Ducati 33:37.371
4 Troy Corser (Aus) Suzuki 33:39.991
5 Andrew Pitt (Aus) Yamaha 33:40.447
6 Lorenzo Lanzi (It) Ducati 33:50.533
7 Max Neukirchner (Ger) Honda 33:51.308
8 Karl Muggeridge (Aus) Honda 33:56.391
9 Norick Abe (Jpn) Yamaha 34:04.854
10 Ben Bostrom (US) Honda 34:08.124

Championship standings (after nine of 12 rounds):
1 Troy Corser 370 points
2 Chris Vermeulen 284
3 Regis Laconi (Fr) Ducati 214
4 Noriyuki Haga 203
5 James Toseland 197