Yeah, based on the information you've got connected to the players, venue, recent match history, and several data, it is easy to come up with the right prediction on the outcome of the match. However, at times things go out of our prediction, and this is all because of the luck factor. This way luck also has its role. To me, sports betting is kind of 85% skill and the remaining 15% depends on luck.
Of course, no matter how well you know about sports, there may always be some circumstances that do not depend on you, but may affect the outcome of the meeting. Therefore, from time to time we observe how an outsider defeats the leader of the championship and it is difficult to predict such a result.
Since it's kind of difficult to predict the results of the match because some unpredictable circumstance might occur during the game play time, a gambler can not be a hundred percent sure of his predictions when the game hasn't ended. This is why gamble is based on luck, although your skill might also help you achieve a winning but luck plays a big role in gambe which makes luck very important while you are gambling.