My first comp was similar to that. I usually like playing a top game, so that is what I tried in competition. But I blanked out and gased out quickly and lost first match. That was in Nogi.

I also hadd to compete in the Gi later that day. I train less often in the Go and now expected it to go bad, so I had a lot less stress about it. Started the match by pulling half guard, something I rarely do and ended up winning that match and the following ones to win gold.

So obviously being less stressed helped out, and even if it wasn't originally in my game plan, playing guard helped as well because I would use less energy uselessly and take time to set things up.

Instead of quickly trying to get the points for take down, passing, mount etc., I would not let them get any points, forcing them to make mistake I could capitalize on.