He was fighting to kill Bucky. Bucky & Steve were just trying to disable his armor.

I think the movie meant that nobody won. Both sides lost their primary weapons, Cap his shield and Bucky his arm, and Tony suit is damaged beyond repair (which is a problem after getting rid of or losing 40 suits in Iron Man 3).

Tony Might have won the battle but he was going to lose the war at the time if he keeps his Hatred against Steve and Buck. Also, Bucky and Steve was just trying to survive it while Tony was trying to Murdered both of them.

The fight was cool

Well I wouldn't say he won since Steve was the one came on top because he smashed his shield into Tony's arc-reactor

So Steve won actually

But Steve lost his shield.