#Assuming a willing target, this would take two of your own actions. 

With the first action, you'd cast Haste, targeting the enemy. The second action would then be used to Ready an action, with which you'd release concentration on the opponent's turn. You'd have to come up with some perceivable trigger, but that would be the only way to end concentration on the enemy's turn without being attacked. 

The risk of this method is that without Action Surge from two levels of fighter, you'd be unable to do this in a single round, meaning the enemy would reap at least one round's benefit from the *haste* spell.

I assume a willing target with all of this, because I unfortunately cannot say whether there's a way to make a target willing.