The superlative degree of adjectives or adverbs is formed by putting the definite article or a possessive pronoun before the comparative. When el (la, lo) is used as the article, both the comparative and superlative have the same form.
Let's look at a few examples:
Positive: bueno - good
Comparative: mejor - better
Superlative: el mejor - best
Positive: rico - rich
Comparative: más rico - richer
Superlative: el más rico - richest
Positive: aprisa - quickly
Comparative: más aprisa - more quickly
Superlative: lo más aprisa - most quickly
That man is the richest of all.
That is my best pen.
That man is the richer of the two.
After a superlative de is used for the English ' in.'
Paris is the most beautiful city in the world.