Heading into Saturday's Game 7, the Sixers hadn't beat the Boston Celtics in a playoff series since 1982 . The Celtics were 32-0 all-time after going up 3-1 in a playoff series, while the Sixers were 0-18 all-time after going down 3-1. The Celtics were up 3-1 against the Sixers in the first round of the playoffs this year after their second 32-point blowout in Game 4. They were headed back to Boston for Game 5 and figured to take care of business there and then. The Sixers were plus-2200 underdogs to win the series going into that game, per Patrick Everson of Vegas Insider. Instead, the Sixers defied 40-plus years of history. After beating the Celtics by double digits in both Games 5 and 6, the Sixers got off to a double-digit lead in the first quarter of Game 7. The Celtics battled back in the second quarter and cut the Sixers' lead to five at halftime, although the Sixers jumped back out to an 18-point lead late in the third quarter.…