A no. of factors, apart from managers' style, would never allow such score line to happen.
1st of all your starting 11 is good enough, instead of running all over the places.
After scoring 2 goals, your players start thinking about the next game 3 days from now, hopefully not too early.
MANAGER must rotate with fresh legs and hungry players, that is assuming your manager DOES rotate. This was my 1st bitterness on ETH after he ran Martinez to his broken leg on his debug season.
Then assuming your sub players are as good and as hungry as the starting 11. You will need 2-3 sub at least to make any real impact.
You also need to assume your opponent giving up somehow.
IMO 3-0 is about the best that you can hope for. 2 goals for margin, keep focusing and not giving away anything, then take advantage of the extra space from opponent in the final 10min, to kill off the game.