I needed something to shift my mind from the horror I have witnessed in Atlanta so here goes my attempt to show the Celtics have been here before and won it all and that hopefully, we will do it again. 
I tried to go back in our history to see if we had ever been pushed to the limit in round 1 and still won the title..I had to go far back to the 60's but here is what I found- I know there were no semi finals but we still got pushed in round 1 nonetheless and managed to win it all. I could only find 2 other teams in the past 20 years that managed to do this but there opponent was a bit tougher then ours. Utah in 95 won 60 games. The one team that has some similarities to ours record wise was the following....
Sacramento was 44-38 in 2000 and pushed the 67 win Lakers to the max...I know Sac was better but they were also young like Atlanta and the Lakers were dominant like we were this year and they  reacted with a 4-1 beating of the Suns the following series. Hopefully, we will follow the trajectory of the Lakers in 2000..( I know we have a coaching handicap but we also have 3 players that should be able to take over a game in spite of him)
Celtics being pushed to limit in first round with title as end result
1966 -- defeated Cincinnati, 3-2, division semifinals
        defeated Philadelphia, 4-1, division finals
        defeated LA Lakers, 4-3, NBA Finals
        WON NBA CHAMPIONSHIP
1965 -- defeated Philadelphia, 4-3, division finals
        defeated LA Lakers, 4-1, NBA Finals
        WON NBA CHAMPIONSHIP
1963 -- defeated Cincinnati, 4-3, division finals
        defeated LA Lakers, 4-2, NBA Finals
        WON NBA CHAMPIONSHIP
1963 -- defeated Cincinnati, 4-3, division finals
        defeated LA Lakers, 4-2, NBA Finals
        WON NBA CHAMPIONSHIP
1962 -- defeated Philadelphia, 4-3, division finals
        defeated LA Lakers, 4-3, NBA Finals
        WON NBA CHAMPIONSHIP
1959 -- defeated Syracuse, 4-3, division finals
        defeated Minneapolis, 4-0, NBA Finals
        WON NBA CHAMPIONSHIP
2007- Defeated Hawks, 4-3, first round
      Defeated Cavs, 4-2, conference semifinals
      Defeated Pistons, 4-2, conference finals
      Defeated Lakers, 4-3, NBA Finals
      Won NBA CHAMPIONSHIP
In 95, the Rockets got pushed to the limit in the first round and again in the 2nd round and won
1995 -- defeated Utah, 3-2, first round
        defeated Phoenix, 4-3, conference semifinals
        defeated San Antonio, 4-2, conference finals
        defeated Orlando, 4-0, NBA Finals
        WON NBA CHAMPIONSHIP
Lakers- Closest to our record and hopefully the results will follow as well
2000 -- defeated Sacramento, 3-2, first round
        defeated Phoenix, 4-1, conference semifinals
        defeated Portland, 4-3, conference finals
        defeated Indiana, 4-2, NBA Finals
        WON NBA CHAMPIONSHIP