Greg Hancock, last year's Oxford Silver Machine skipper, roared to his first Grand Prix victory since his Cardiff success last year with the sweetest piece of riding you could wish to see in Latvia.

The American upstaged Antonio Lindback in the final at Daugavpils on Saturday.

Hancock's 25 points moves him on to 124, 15 clear of third-place finisher Nicki Pedersen, and in pole position for the overall silver medal.

For Lindback, it was an unfortunate case of history repeating itself as he held a commanding led in the initial stages of the decider until Pedersen fell under the challenge of Andreas Jonsson exiting turn four.

It was one of the most difficult refereeing calls of the season, but Jonsson was excluded and had to be content with 16 points.

Lindback, meanwhile, had lost the World Under 21 final in similar circumstances last week, but could still be proud of his efforts.

Hancock said: "We've been working so hard all year and we've made a few silly mistakes and had some bad luck, but it all came together on the night.

"I've been struggling a little recently, but it looks like we've solved our motor problems and it's a great result for me.

"The silver medal is what I have to go for at the moment, but the world championship itself is what it's all about and I still feel I have another one in me!"

Result (top six): Greg Hancock (USA) 25, Antonio Lindback (Swe) 20, Nicki Pedersen (Den) 18, Andreas Jonsson (Swe) 16, Jason Crump (Aus) 11, Matej Zagar (Slov) 11, Scott Nicholls (GB) 9, Leigh Adams (Aus) 8, Bjarne Pedersen (Den) 7, Jarek Hampel (Pol) 7, Piotr Protasiewicz (Pol) 4, Hans Andersen (Den) 4, Tomasz Gollob (Pol) 4, Kjastas Puodzhuks (Lat) 4, Niels-Kristian Iversen (Den) 4, Lee Richardson (GB) 0, Grigorijis Laguta (Lat, res) 0, Andrejs Korolovs (Lat, res) 0.

Standings (top six after round 9 of 10): Jason Crump 181, Greg Hancock 124, Nicki Pedersen 109, Andreas Jonsson 107, Leigh Adams 100, Hans Andersen 92, Matej Zagar 89, Antonio Lindback 86, Jarek Hampel 85, Scott Nicholls 76, Tomasz Gollob 76, Bjarne Pedersen 75, Niels-Kristian Iversen 48, Tony Rickardsson 41, Lee Richardson 38, Piotr Protasiewicz 27.