What sup peeps

I went to go play at a Pioneer RCQ over at a local shop in a neighboring city to test my skills as a player but also gain experience in the competitive side of magic since I mostly play commander. As you can tell from the title I played greasefang, I went with abzan since I've tried mardu and esper, but abzan felt better in my opinion. Anyway during my 4th round match up I went against esper control which I knew was gonna be somewhat of difficult road for me, but during my 2nd game there was a interaction that sort threw me off my game and like got me confused at one point. so I wanted to get some more opinions on this situation.

So what happen was that I announce to my opponent that I was going to move to combat to trigger greasefang's ability to grab a vehicle from my graveyard, but my opponent said that I couldn't do that because I already move to combat and I miss that trigger. So I was confused and like sat there puzzled for a moment because before I was doing that same thing earlier with no issues, because in my mind the ability goes on to the stack and then I pass priority to them to see if they want to do anything before the vehicle comes out. Since it was the heat of the moment I had like a brain fart and just said "ok.....I guess it w/e then" and went to combat without pulling a vehicle out with greasefang.

In the end I lost to that match up because of all the answer he had to stop me from doing my combo, but I felt that comment like threw me off my momentum and I ended up not making a smart decision by calling a judge. It was only one instance of this happening but I just felt salty coming out of that match up.

what do you guys think???