Because he dominated a skilled swordsman in Quinlan Vos, is acclaimed as one of the greatest bladesbeings ever produced by the Order, and has demonstrated high levels of martial skill and discipline. He is an excellent lightsaber duelist, and a passable Force user.
Now, is that enough to top Kyle? I doubt it, but take from it what you will; I doubt ILS would have more to add to the subject.
NewGuy essentially covered it. Kolar's main skill lies in dueling. His ability in augmentation hasn't been expounded on much, but by reasonable inference he is as fast as the next fighter. And his Force powers aren't great.
If Kyle opted to duel Kolar primarily I would give the win to Kolar. I honestly might even give Kolar a majority win over Kyle anyway if his use of the Force wasn't too substantial.