Imagine you are 1 v 1 with a defender, you accelerate to one side, and once both of you are at full pace you change direction. If the defender knows that I will change direction, but doesn't know when, will it work?
The defender has to watch the striker to react to his movements and the striker, running towards the defender tries to trick him out. The striker must therefore try to "deceive" the defender with movements in order to get through on the other side where he has deceived the defender. What if the striker fakes left, then right and then left? So he plays the defender "dizzy" and gets past the defender more easily. Thus, the pace, agility and skill are crucial for both players.
Although the pace is probably the most decisive, because if the striker accelerates, the defender has to react and run after.
I play left wing in soccer and believe me you have no idea how effective a simple but well performed cut or turn is when sprinting down the sideline. You don't need anything fancy, just sprint, use the outside of you foot to cut away from the sideline and behind the defender into wide open space.
However, executing this takes practice, when you are practicing first work on just running straight and then planting one foot, turning 90 degrees and bouncing off that foot. Start at a jog and once you get comfortable, go faster and faster till you are sprinting. As you get good at this, start practicing with a ball.
Most defenders will be expecting a cut eventually, but won't be able to react in time. That being said, it is important to be unpredictable on the field, so firstly, don't cut in the same place each time. Second, learn one or two other moves but KEEP IT SIMPLE!! No double or triple lunges/stopovers or anything like that. I use two moves: 1) faking a cross (you really have to sell it) 2) step in front of the ball, putting myself between me and the defender, and then turn and roll the ball backwards and away from the line (similar to a maradona but more control.)
But believe me the cut is litterally the most effective thing when sprinting down the line.