ATLANTA (AP):Atlanta and San Antonio took imposing 2-0 leads in their opening-round playoff series with emphatic victories over Boston and Memphis on Tuesday night.The Hawks held the Celtics to the lowest-scoring first quarter in the playoffs since the NBA went to the shot clock, building a 21-point lead and holding on despite an ugly shooting performance of their own for an 89-72 victory and a strong hold on their Eastern Conference series.Al Horford and Kyle Korver led Atlanta with 17 points apiece, but this game was essentially decided in the first 12 minutes.The Hawks started nine of 13 from the field, knocking down six from beyond the three-point arc. Korver made four from long range, a big turnaround from a one-of-10 performance in Game One that didn’t include any threes. Atlanta led 24-3 just 6 1/2 minutes into the game.Even after failing to score the rest of the period, the Hawks still led 24-7 heading to the second.Shaking off a dismal performance in the playoff opener, Korver swished four three-pointers in the opening minutes to propel Atlanta to a stunning 21-point lead before many fans had settled into their seats. There wasn’t much doubt after that.MISSED SHOTS”We all have pride, right?” said Korver, who went one of 10 on Saturday and missed all seven of his three-point attempts. “I wanted to come out and play better the second game.”As good as Korver and the Hawks were in the early going, this one will be remembered more for the Celtics’ grisly start.”I don’t know what it is,” said Boston’s Jae Crowder, looking a bit shell-shocked after scoring just two points on one-of-nine shooting. “But we’ve got to change something.”Crowder had plenty of company in his shooting misery.Boston star Isaiah Thomas was held to 16 points on four-of-15 shooting, going one of six beyond the arc. Marcus Smart stepped in for the injured Avery Bradley and went one of 11, also making just one of six from three-point range. The Celtics finished at 32 per cent overall (28 of 88), five of 28 from long range.Game Three is tomorrow night in Boston.San Antonio were even more impressive than the Hawks in beating the Grizzlies 94-68. Patty Mills had 16 points, Kawhi Leonard added 13 and San Antonio never trailed in sweeping the first two games.