I watched a dude suffer a brutally broken jaw, continue on and win the fight. I watched a dude with a concussion, fall around on the canvas and didn't remember anything after the 2nd round, continue on and win the fight. I watched 2 fighters with a broken orbital bone continue on and go the distance. If Vitali wanted to CONTINUE....he should've been allowed too. The Doctor stopped the fight, not him, so why would I say "he quit"?
He was beating Lennox Lewis 4-2 over the 6 rounds they actually fought, Lewis claimed he would fight him later that year in a rematch, and then retired out the blue. If he was confident he could win, he wouldn't have turned down the rematch and the purse that came along with it. Simple as that.