Casey Stoner took the honours in the Italian MotoGP Grand Prix on Sunday to move top of the standings and end Valentino Rossi's long reign at his home race.
The Australian Ducati rider, who started second on the grid, held his nerve on the 23 laps after riders had to switch bikes when rainy skies cleared and new tyres were needed.
'It was a difficult race. I thought more than once that the chance to win had gone,' the 2007 champion told reporters.
Previous championship leader Jorge Lorenzo, who fell in practice and made a terrible start from pole position, recovered to finish second on his Yamaha and now trails Stoner by four points.
World champion Rossi, who had been bidding for an eighth straight win in Italy, came in third after changing to hard tyres with 13 laps to go rather than softs like many rivals.
'It was better to put the softs on but in practice I struggled with the softs,' he said. 'I'd won seven in a row so that's ok.'
Rossi lies third overall, nine behind Stoner after just five rounds. The next race in the Catalan MotoGP on 14 June.
Spain's Dani Pedrosa, dogged by injuries of late, suffered another fall and was taken away on a stretcher.
Italian Mattia Pasini on an Aprilia triumphed in the 250cc class after a thrilling contest in the earlier rain when he just managed to hold off compatriot and last year's champion Marco Simoncelli.
A collision between Simoncelli and championship leader Alvaro Bautista midway through had threatened their chances in the race but they stormed back to put real pressure on Pasini, who was overtaken once but just managed to reach the line first.
