China's fleet reached Africa decades before Columbus sailed.
Between 1405 and 1433 Admiral Zheng He led seven expeditions. The first fleet counted 317 ships and nearly 28,000 men – Columbus set out in 1492 with three. Zheng He reached India, Arabia and the East African coast. After that the Ming court discontinued the voyages.
Useful: A technological lead decides nothing if a government stops pursuing it.
Source: en.wikipedia.org