Before he joined the enemy, Ray Allen helped knock them out of the playoffs.
On April 27, 2020 -- 10 years ago Monday -- the Celtics carried a 3-1 series lead over the Miami Heat into Boston for Game 5 of their first-round playoff series.
Dwyane Wade and the Heat hung around (this was before LeBron James and Chris Bosh came to town), but Boston took care of business thanks in large part to Allen, who scored a team-high 24 points while going 5-of-6 from 3-point range to lead the Celtics to a 96-86 win.
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The C's advanced to the second round with the victory and made it all the way to the NBA Finals before falling to the Los Angeles Lakers in seven games.
Here are a couple other notable April 27 performances from the C's, who are 6-4 all-time in games played on this date:
April 27, 2003: Paul Pierce joins Larry Bird and John Havlicek as the only Celtics players to record at least 37 points, 10 rebounds and seven assists in a postseason game as Boston defeats the Indiana Pacers 102-92 in a first-round matchup.
April 27, 1992: The late Reggie Lewis drops 32 points to help the Celtics beat the Pacers (again) 102-98 and complete the first-round playoff sweep.