The Detroit Pistons dealt the Boston Celtics their first home loss of the post-season with a 103-97 victory on Thursday that tied their best-of-seven Eastern Conference finals at 1-1. Playing an expansive game, the Pistons led by seven points at halftime, by nine after three quarters and had an 86-75 lead in the fourth quarter before they withstood a Celtics rally. Boston, winner of all nine previous playoff games on its home court and boosted by a return to form by Ray Allen, ran off eight points in a row to make it 86-83 and narrowed the gap to just two points before the Pistons steadied themselves. Richard Hamilton led Detroit with 25 points and Chauncey Billups, held to nine points in the series opener, added 19. The Celtics relied on their big three - Paul Pierce had 26 points, Allen 25 and Kevin Garnett contributed 24. The series shifts to Detroit for the next two games, with Game Three on Saturday. “Tonight we just wanted to be aggressive and get the ball to the basket, and we did a good job of doing that,” Hamilton told reporters. “Just keep attacking.” The Pistons and Celtics had almost identical shooting percentages of nearly 50 percent from the floor, but Detroit's assertiveness earned it six more points from the free-throw line, which matched the winning margin. Detroit shot 28-of-32 from the stripe, to 22-of-25 for Boston as the Pistons won for the fourth time away from home this post-season. Billups, rusty in the opener in returning from a hamstring injury, made a critical lay-up off on an inbounds pass with three seconds on the shot clock and 18.7 seconds left in the game to give Detroit a 100-94 lead for some breathing room. “It's a big win,” Hamilton said. “I thought our guys really knuckled down, hit first, played with intensity to get a win.” Boston coach Doc Rivers credited Detroit's effort but said fatigue might have caught up with his team, who were extended to seven games by LeBron James and the Cavaliers, while Detroit rested about a week after dismissing Orlando in five. “To me it's always about defense and we didn't have a good defensive night,” Rivers said. “We lost the game because we gave up too many points. I didn't think fatigue would catch up to us in Game One because the adrenalin of Game Seven (against Cleveland) would carry over,” he said. “I was worried about this one.” “We were a step slow in our rotations,” Pierce said about the Celtics' defense. Garnett said in crucial moments of the fourth quarter, “it was like we were running in sand.” “When we needed stops, we didn't get them,” he added. The Celtics have yet to win a road game in the playoffs, but now they must if the team with the best regular season record in the NBA is to reach the championship finals. “Doc said there is going to be a time when we've got to get a win on the road,” Garnett said. “Now we're up close and personal with that dilemma.”