Seventy-one riders rolled off the start line in Milan at 6:25 am in beautiful weather.
The opening pace was high through Ovada (113 km into the race / 287 km), where the peloton remained intact.
On the Passo Turchino (131 km / 287 km), Henri Pelissier (Fra) launched the first to attack, but Ezio Corlaita (Ita) and Costante Girardengo (Ita) answer the move.
At the summit Girardengo sprinted away and won the cash prize for the Grand Prix of the Mountains.
The pace remained high in the descent with a single file peloton. Gaps began to appear.
In Voltri (155 km / 287 km), the leading group of twelve included the Girardengo (Stucchi) and Carlo Belloni (Bianchi).
In Arenzano (166 km / 287 km), the pace slowed and the peloton regrouped.
In Piani d'Invrea (175 km / 287 km), Girardengo attacked with Giuseppe Azzini (Stucchi), only Giovanni Brunero (Legnano) and Alfredo Sivocci (Legnano) managed to stay with the leaders.
Azzini and Sivocci attacked at the begiimg of the Capo Berta climb (262 km / 287 km), but a vigilant Girardengo chased hard and passed them over the summit.
The final selection happened on the descent of the Capo Berta, Girardengo and Brunero separated from the pack and rode into San Remo together.