Nick Skelton, the first Briton to attempt the 12-fence course, jumped the only double clear round of the competition on Everest Limited Edition. But Michael Whitaker, jumping second for the British team on Henderson Monsanta, had a refusal in the treble in both his rounds for the discard scores of 11.5 and 12.5 faults. David Broome, competing in his 100th Nations Cup, had two eight- fault rounds with Ancit Countryman, who was not suited by the soft going.
A clear first round from John Whitaker and Henderson Milton had left Britain leading from Italy, with four nations (including Switzerland) in equal third place. France, fielding two of their Olympic bronze medal team, made a disheartening start to be seventh after the first round and neither they - nor the Belgians who were lying eighth and last - took any further part.
The Swiss responded with clear rounds from their two Olympic riders, Markus Fuchs on Chandor and Willi Melliger on Quinta C as the British lead began to look vulnerable. Victory was still possible if Milton were to repeat his earlier clear round, but this time the grey struck a pole over the last fence in the treble to make the jump-off necessary.
Both Lucinda IV, the mount of Switzerland's Philippe Guerdat, and Skelton with Limited Edition, lowered the last jump-off fence, but the Briton's time was faster. The pendulum then swung in Switzerland's favour with a clear round from Chandor and four faults, at the first fence, from Monsanta. It was all over after Stefan Lauber went clear on Lugana and Broome had a single error on Countryman.
Italy went well to finish third with Germany, the Netherlands and the United States bringing up the rear. Germany's Olympic champion, Ludger Beerbaum, had a difficult second round on Rush On, who took exception to the water to incur 22.5 faults.
Beerbaum has lost the ride on the Olympic winner, Classic Touch, but gained a new mount in the runner-up, Ratina Z, who was bought by his Almox sponsors last week.
SAN MARINO NATIONS CUP (Modena, Italy): 1 Switzerland 20 faults (four in jump-off);
2 Great Britain 20 (12 in jump-off); 3 Italy 36.5;
4 Germany 40; 5 Netherlands 48; 6 United States 78.5.Reuse content