In C1 thru C6 enter:
=rand()
In A1 thru A3 enter:
=MATCH(LARGE($C$1:$C$6,1),$C$1:$C$6,FALSE)
=MATCH(LARGE($C$1:$C$6,2),$C$1:$C$6,FALSE)
=MATCH(LARGE($C$1:$C$6,3),$C$1:$C$6,FALSE)
In B1 thru B3 enter:
=MATCH(LARGE($C$1:$C$6,4),$C$1:$C$6,FALSE)
=MATCH(LARGE($C$1:$C$6,5),$C$1:$C$6,FALSE)
=MATCH(LARGE($C$1:$C$6,6),$C$1:$C$6,FALSE)
We see something like:
1 6 0.68334192
4 5 0.312318543
3 2 0.491735076
0.541504961
0.331550966
0.373367917
So at one match Team #1 plays Team #6
Team # 4 plays team # 5
Team # 3 plays Team # 2
You can create as many random pairings as you need simply by touching F9.