"The best engineer won."
Translation:El mejor ingeniero ganó.
There are several cases in which adjectives will appear before the corresponding noun. Check out these two articles: https://www.spanishdict.com/guide/adjective-placement and (the section "How to deal with Spanish adjective order")
Oops, my fault. I forgot to include the second link in my post. Here you go: https://www.realfastspanish.com/grammar/spanish-adjectives
Sources vary as far as the reasoning for the position of "mejor". The first article, from SpanishDict, would consider it part of the section "Essential/inherit adjectives", which is to say that the fact that the engineer is the best (/better) is an assumed quality rather than a description. The second article mentions "mejor" specifically as a rule of its own. Use whichever reasoning makes sense to you, the important part is that "mejor" should go before the noun. :)