u/sahnti

I am very new to playing multiplayer, and I see the same thing every fight. I dont throw volume punches, I try to counter so I do a lot of rolls and slips and blocks. I end up throwing about half the punches of my opponents. How do those guys maintain thatb intensity for 7-8 rounds and knock me out and I get gassed out so fast? How can I last longer (lol)?

Ps: fight night champion on xbox