The Saints led from the start on Saturday at the MCG and coasted to a 49-point win over the second-bottom Tigers, 14.10 (94) to 6.9 (45).
Owens kicked a career-best five goals and the 11th-placed Saints remained in the hunt for a wildcard berth with their seventh straight win over Richmond, at least for one more day.
They must beat Gold Coast next week and need Carlton to lose their last two games. But the Western Bulldogs will be without Marcus Bontempelli and Tim English on Sunday when they play the Blues.
Brad Hill racked up a game-best 41 disposals and Max Hall also was prolific with 40 possessions, as they cut up the Tigers through the middle of the ground.
Prestia had a team-high 27 disposals, and his three-time premiership teammate Broad was denied a rare goal seconds before the final siren. The pair were chaired off the field.
The Saints had made five changes for this game, headlined by the hamstring injury to star midfielder Nasiah Wanganeen-Milera.
They dominated the lowly Tigers from the start, kicking the first two goals and taking a 10-point lead into the quarter-time break.
With Hill and Hall running rampant, the Saints killed off the game in the second term. They kicked four goals to two and led by 25 points at the main break.
Jack Higgins summed up the scrappy end to the second quarter with a horrible set shot that barely scraped through for a behind.
The free-kick count at halftime was 11-1 in St Kilda's favour. For the rest of the game, any Richmond free attracted a loud cheer from their frustrated fans.
The other key stat for Richmond was the number of guernseys that Prestia wore in his swansong game - at least five, including a long sleeve - as he undoubtedly maximised the merchandise opportunity.
Richmond's forwards were starved of chances and Tom Lynch, in his 250th game, did not kick his only goal until early in the final quarter.
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