In a recent game, my partner and I were winning 8-4. I dealt and was holding this:





Upcard was the

First seat orders me up and I discard the nine of spades.
First seat then leads the

At this point, I'm wondering what in the world the guy in first seat called with!
I lead back the Ace of Diamonds, first seat then throws off the



I then lead back the two bowers for the euchre. I end up taking all five tricks.
Any ideas what first seat was actually thinking? I could see ordering the right up as a block, but we were already winning 8-4! Blocking would hand us the game...