The most frustrating achievement in the game. Here's how I did it; 2 controllers, local MP. Pick Barcelona vs. B36 (Faroe Islands). You use Barcelona, 2nd controller is B36. Using Barcelona (1st controller), take the ball into the B36 end and kick it out of bounds to the side about parallel to the 6 yd box (the smaller box around the B36 net). Using the 2nd controller (B36), push AWAY from the net (right or left) to get height on the ball and hold A on the throw in. The ball will bounce into the middle of the field, and there should be a Barca player running in towards it from just outside the larger box in the middle of the field. Hit it straight in with the A button. Timing is everything, and you will miss the ball completely or kick it more often than not, but persevere and you will get it. I tried many different methods, and this was the only one I could get to work consistently. Just keep at it.