Sentence:  But as the half progressed, Liverpool's pressure and high-tempo passing game increased United's frustration and it threatened to boil over on the stroke of half-time when Van Persie, who had already been booked, was involved in angry verbal exchanges with several Liverpool players, <WSD>particularly</WSD> Gerrard. 
Meaning of the word marked with <WSD> tags:  Specifically, uniquely or individually.