Could the Dominican Order hypothetically defeat Blessed Gerard's order?
Let’s work this out in a step by step way to be sure we have the right answer.
no
The Dominican Order is a Catholic group of friars that several priestly vows.

Blessed Gerard was the founder of the Order of St John of Jerusalem (Knights Hospitaller).

The Order of St John of Jerusalem (Knights Hospitaller) were a well trained Catholic military order that fought in the Crusades.

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So, the answer is no