Surprising Riposte( Drow of the Underdark, p. 52)
[Fighter Bonus Feat, General]
Through deft maneuvering, you unravel your opponent's defenses
If you deal damage to an opponent in the same round that you successfully feinted against it, it becomes flatfooted. This effect lasts 1 round or until the opponent's next turn, whichever comes first.
Opponents that can't be caught flat-footed, such as characters who have uncanny dodge, cannot be affected by Surprising Riposte.
A fighter can select Surprising Riposte as a fighter bonus feat.