On February 14, 2007, the Boston Celtics  blew out to the Milwaukee Bucks  to end an abysmal 18-game losing streak that devastated the organization. On December 23, 2008, they blew out the Philadelphia 76ers  to break the franchise record of 18 consecutive games and capture their 19th straight win. They are two 18-game streaks with very different results.
Biggest heartbreaker: 93-89 loss to the San Antonio Spurs 
Paul Pierce then: Pierce was sidelined for 35 games and described the losing streak as ‘watching his little brothers get beat up.’ His 25.0 points, 5.9 rebounds, and 4.1 assists were not enough to overcome a 24-58 record.
Doc Rivers  then: On the hotseat the entire season, fans chanted ‘Fire Doc’ and were outraged that he didn’t get the boot.
Emerging leader: Al Jefferson 
After Paul Pierce and Tony Allen  went down with injuries, Jefferson emerged as one of the most promising big men in the league. That season Big Al averaged 16 points and 11 rebounds, a performance good enough to become the centerpiece of the Kevin Garnett  trade.
2008-2009 Winning Streak
How it all began: The Celtics beat the Bucks 102-97 in overtime on November 15, 2008.
Biggest blowout: 102-78 win over the Philadelphia 76ers
Paul Pierce now: ‘Has any Boston Celtics team ever lost 18 in a row? I’ve done that,’ he asked with a chuckle. Pierce can laugh at the 2007 season now that he is the reigning NBA Finals  MVP and his 18.5 points, 5.8 rebounds, and 3.8 assists are enough to keep the Celtics atop the standings.
Doc Rivers now: After leading his team to a championship, Rivers became the third coach to ever win three consecutive Eastern Conference Coach of the Month honors.
Emerging Leader: Rajon Rondo 
So much for the Big Three. Rondo has not only emerged as the spark plug of the Celtics but one of the most versatile point guards in the NBA. Whether he’s lobbing it to KG, driving to the lane, or knocking down an improved jumpshot, his triple-double was a sign of things to come.
The Celtics will look to continue their winning streak against the Los Angeles Lakers  on Christmas Day.