I mentioned this a while back but it bears repeating. Here are the Celtics' results against Houston and GS this year:
vs GS: W, 92-88
vs Hou: W, 99-98
at GS: L, 109-105
at Hou: L, 123-120
And I know the Celtics are a much different team, but here's last year's results as well:
vs GS: L, 104-88
at Hou: L, 107-106
vs Hou: W, 120-109
at GS: W, 99-86
So they're 2-2 against GS and 2-2 against Houston over the past two seasons. Three of the four losses were within 4 points (one blowout). Two of the four wins were within 4 points (two blowouts). Total combined score:
Boston: 829
Opp: 824
If - and I know there's a long way to go - they advance to the NBA finals, they would appear to stand as good a chance as anyone to hang with, and maybe even beat, either Houston or Golden State.