He very well could have been but I've just watched it again. He gets low blowed before the right hand, avoids a fair amount of punches after it and goes down to the low blows at the end. All together it happens quite a few times, maybe 5 or 6 low blows all together in one round.
He could have continued but would he have won? Idk, still a shitty way to end such an important fight. Ward should have lost a point, not won by TKO at that moment. It's not out the realms of possibility that he could have been DQ'd for consistent fouls.
In the long run, Ward probably wins that specific fight though but you never know since it was taken from us via illegal shots that were deemed legal.