the press works in spurts because it is a change of pace, and because Syracuse almost always has top notch, rangy athletes.
The zone is designed to force the opposition to slow down and have to work the ball around to get good shots. Syracuse's players know the typical passes the offense makes, and when they play the zone at a high level they are active, anticipate well, and can generate turnovers by picking off passes and introduce doubt and hesitancy into the opposition, making them passive and, ultimately, settling for long jumpshots. Patient, methodical teams are willing to work the zone, making Syracuse move and scramble and take advantage of breakdowns to get easy shots. The opposition can get into a rhythm of attacking the zone and put the Syracuse defense on its heels. The selective use of the press speeds up the other team. Sometimes Syracuse generates turnovers, and sometimes they give up layups. But what the press does is knock the methodical, well executing offense out of its attacking rhythm. That's exactly what happened to UVA, and you saw when Syracuse called off the press and retreated to the typical zone, UVA wasn't attacking it as well as they had been earlier in the half.