Portugal used to be the leading European maritime power.
In the last half of the 15th century they pushed south along the coast of Africa, around the Cape of Good Hope and into the Indian Ocean. They had trade and projected military power as far as India, the Spice Islands, China and even Japan. They had the best ships and the most advanced navigational technology, and an infrastructure to support it all. Columbus sailed West because the Portuguese controlled the routes to the East.
Someone had to be first. But there is no guarantee they will hold that position forever.