Bulgarian major Ivanov with white flag surrendering to Serbian 7th Danube regiment near Kumanovo

The underdog bites

At Cer and Kolubara, Serbian forces threw back Austria‑Hungary with heavy losses—one of the major upset victories of the twentieth century.

World War I: Serbia’s Stunning Upset

Bulgarian major Ivanov with white flag surrendering to Serbian 7th Danube regiment near Kumanovo

The ripple effect

Vienna kept sizeable forces tied to Serbia, weakening its fight against Russia.

World War I: Serbia’s Stunning Upset

World War I: Serbia’s Stunning Upset | DeepSwipe