In his first Tour de France in 1909, he abandoned early due to wintery conditions during the month of July, but not before he managed a Stage 2 second place behind Tour winner Fracois Faber. The following year he went head-to-head with Alcyon teammate Faber who led confortably until colliding with a dog at the foot of the Pyrenees. Lapize finally won by just 4 points helped by a number of punctures to Faber's bike on the final stage from Caen to Paris. In a total of six starts in the Tour de France between 1909 and 1914, this victory was the only one he finished.
Octave Lapize is noted for looking at some Tour officials on the climb of the Col du Tourmalet in the 1910 Tour de France and yelling, "Vous estes des assassins! Oui, des assassins ( French for 'You are murderers! Yes, murderers!')" The stage in question was 326 kilometers in length, featured 7 brutal climbs, and was raced on unsealed roads with single-gear bicycles.
World War I ended his cycling career. As a fighter pilot in the French army, Octave Lapize was shot down near Flirey, Meuthe-et- Moselle on July 14, 1917. Severly injured, he died in a hospital in Toul.