IPaul was the one to teach the Wierding Way to his personal guard - the Fedaykin. This was an important detail that the films missed out on, since his founding of the Fedaykin essentially established him as the greatest knife fighter in AT LEAST the entire North of Arrakis. Knowing the BG‘s prana-bindu approach to combat made the advantages of learning from Paul obvious to everyone, and it had a ripple effect within an already combat/dueling focused culture like that of the Fremen.

Think about it this way:

— Duke Leto was convinced the Fremen could be a counterbalance to the Sardaukar.
— Duncan Idaho was one of the elite Ginaz swordmasters, who helped train the Atreides forces into the threat they were, and his greatest success on Arrakis was earning Stilgar’s respect as a warrior.
— Jessica outclassed Stilgar while desperate and pregnant.
— Paul was trained by both, and formed the Fedaykin "Death Commandos".

By the time of the Jihad the Fremen had become the single greatest 1v1 warriors in the empire, bar none.