When looking at Starkiller and Luke......
Starkiller was placed in the movie context he would be a unstable Force user who is naturally connected to the Force's wild energy but very little in the area of using it other than in brute force. This means if Starkiller faced Luke it would be interesting.....If Luke is in his empire strikes back or Return of the Jedi....Starkiller strength would be his raw use of the Force in the area of attacking but Luke's ability to find his center within the force and see opportunity...will give Luke an advantage... Luke could sense and exploit Starkiller's inner emotions and conflict..this will weaken starkiller and allow Luke a chance to redeem him or defeat him.
If this is New Hope Luke before Obi-wan....then Luke better hope his dumb luck with the Force saves his butt =)
To win a battle it comes down to prep work, knowing your enemy and psychological warfare...to throw them off/ un-focus