Supervise

I got into a duel... right...

well i had an gemini soldier equipped with supervise
my opponent had an Airknight Pasharat and a face down card ... ok

i attacked, he negated the gemini soldier eff with divine wrath... ok

supervise goes to graveyard triggering the eff, so i can sp summon a normal monster...

Here is the question...

Can i attack with the sp summoned monster?

I say i can, buthe kept telling me no you cant... so...

If you are still in the Battle phase, you can still attack. Nothing to it.

yes that what i said and this guy said no you already attacked since you had no monsters in the field your sp summon is in M2... geez... thanks for the reply

No problem. Only you decide when you want to end the Battle Phase, not your opponent. Special Summons can happen in the Battle Phase by certain card effects, so it's not impossible. There are also cards like Negate Attack and Battle Fader that end the Battle Phase, so there's those to consider.

Other than that, good luck.