Team USA has retained its Motocross of Nations crown after dramatic final moto that saw James Stewart crash whist holding a comfortable lead.

Light rain throughout the day made the hard-packed, but heavily rutted, Donington Park circuit especially treacherous and there were high profile victims from the start of the very first moto.

Ryan Villopoto, who won both his races in front of his home American fans one year ago at Budds creek, crashed on the opening lap of race one - which combined MX1 (450cc) and MX2 (250cc) machines - forcing the Floridian into a come from behind charge that eventually netted tenth position.

Up front, Stewart followed MX1 world champion David Philippaerts for the first two laps before putting his Kawasaki ahead of the Monster Yamaha rider and pulling steadily away to a 21 second victory margin over Frenchman Sebastien Pourcel, who passed Philippaerts on lap six of 16.

Englishman Tommy Searle was the top MX2 rider in ninth place, after factory KTM team-mate and newly crowned world champion Tyla Rattray stalled his machine, all of which contributed to an early leader board showing USA (11), France (13) and Great Britain (15) in the top three positions.

Race two, the MX2 and Open class mix, was dominated by Villopoto - who disappeared to a 24 second victory over Belgium's former MX1 world champion Steve Ramon (Open) and Searle. Tim Ferry brought the second US machine to the lien in ninth, but a poor race for France saw them demoted from the top three and replaced by Italy. After race two, the standings were: USA (21), Italy (33) and Great Britain (33).

Team USA thus looked safe for the final moto, the MX1 and Open class clash, but with plenty to play for behind. Stewart blasted into an early lead from Pourcel, but found the Frenchman a determined opponent and the pair brushed plastic when Pourcel successfully threw his KXF inside Stewart into a tight right hander after the mechanics area.

Stewart soon responded and broke away to what looked like being a perfect 1-1 result, but the reigning AMA Motocross champion crashed - and stalled - with just five laps remaining, dropping him back to 24th by the time he restarted his machine.

With each team's worst race score able to be dropped from the final standings, some frantic calculations followed, but Ferry - just ninth on the lap before Stewart's accident -settled the American nerves by rising to fifth at the chequered flag.