"Shadowless Sword" certainly does not have its reputation for nothing—once the sword qi accelerates, it moves as fast as lightning and thunder, frightfully so.
Although Tang Fu was superior in qinggong, he may be faster than Zhao Tiaotiao's movement technique, but not necessarily faster than Zhao Tiaotiao's moves...
Within ten exchanges, Tang Fu had already been grazed by the sword qi on his waist and arm a couple of times, suffering some flesh wounds.
This was not a good sign...
Tang Fu did not know how much the "Shadowless Sword" drained the physical and Inner Strength nor the upper limit of Zhao Tiaotiao's Inner Strength. If the other side could keep firing off hundreds of strikes without stopping, then he could not afford to waste stamina.
As a master like Tang Fu, "calculating" during combat is very quick, where he barely needs to think, and could make judgments based on experience and instinct.