Your opponent is probably correct, depending on the exact verbal language and shortcuts involved.

Specifically, resolving the spell goes as follows:

1) Spell is declared, targets are declared, mana is paid, etc. Do all the stuffs, spell goes on the stack. You still have priority.

2) You pass priority to the opponent if you have no responses (to your own spell).

3) Your opponent passes priority back, if they have no responses.

4) Spell resolves.

This is from 608.1. Each time all players pass in succession, the spell or ability on top of the stack resolves.


The key here is that you cannot take any actions after step 2) unless your opponent had a response. If your opponent also passes priority, the spell has already resolved, and it's too late to try to copy it. Also, as a standard shortcut, step 2) is always assumed after a spell goes on the stack unless you explicitly state otherwise. You can tell, because otherwise you'd have to say "...pass priority" after every single action you take in a game, and clearly nobody does that.

As a result, if you want to copy (or counter, or whatever else) your own spell, you must state "Hold Priority" in some form, cast your first spell, and then cast your second spell in response - at which point, you verbally release priority and your opponent gets a chance to respond to the copy. If they have no responses, you regain priority and unless you state otherwise are again assumed to be passing it back at which point they get a chance to respond to the original spell.

Here's an example from an SCG event, where a player holds priority to counter his own spell.

New rules question...

When I play a sorcery or instant and my opponent plays an instant in response, can I use Geistblast from my graveyard as a response and copy my original spell?

Why were you playing Geistblast in standard...

... Why were you in U/R, both EMN and SOI does not support either archtype.

I mean you're a cool guy, but if you're playing Geistblast then clearly red wasn't as open as you thought it was.

Red seemed wide open and it was SOI. I'm not very good at draft. I don't know which colours to draft. I should consult you before my next draft probably

your avatar is too dressed

she's the Plain Doll from Bloodborne

That's not right. If you copy a spell, the copy is unrelated to the original and would be on the stack separately regardless on if the original was targeted by a counter or not.
Doesn't matter on the order really since it works same way both ways, just gotta make sure the counter is still on the stack and unresolved when doing it after the counter is cast.

A few questions:

Suppose my opponent attacks with Ulamog, the Ceaseless Hunger and an Elvish Visionary. I have a Thalia, Heretic Cathar on the board and Blessed Alliance in hand. Can I block the Elvish Visionary with Thalia and then cast Blessed Alliance after first strike damage to force him to sacrifice Ulamog?

Yes.

Is there a first strike damage phase if there are no first strike creatures in combat?

Suppose I attack my opponent with Shivan Dragon. He's representing Path to Exile. I want to pump for as much damage as possible, he wants to wait till I finish pumping before using Path. Can I decline to pump, ask him if he's going to do something, and if he does nothing then I pump by one point, ask him if he's going to do something, etc until I decide to stop pumping?

When you attack with the dragon, you can pump when you have priority; after the pump triggers goes on the stack, then he can choose to respond or nah. So basically, what I'm saying is that you can ask him after each pump trigger since it's legal, but ofcourse I wouldn't risk it if I expect my opponent to have removal in that scenario.

A few questions:

Suppose I attack my opponent with Shivan Dragon. He's representing Path to Exile. I want to pump for as much damage as possible, he wants to wait till I finish pumping before using Path. Can I decline to pump, ask him if he's going to do something, and if he does nothing then I pump by one point

You have priority to pump. You pass priority. If he passes priority back without any responses, damage resolves and you do not have another opportunity to pump before you hit him for 5.

I believe in paper magic you get to choose the order of how things happen and you simply order it so Gisela's trigger resolves first and then Nahiri's whiffs.
On duels? Who knows.