If you guys watch the episode there are a lot of details that point to the "Picard Maneuver" as having worked because:
1. the ship accelerated almost instantly to Warp 9 from either sublight or more likely from Warp 2.
2. the Ferengi chose the wrong ship to fire at.
The Ferengi must have possessed FTL sensors since they ambushed the Stargazer as she was traveling by at Warp 2. In all likelihood, the FTL sensors reached some sort of upper limit at Warp 9 detection speeds or refresh rate, IMHO.