Louis' blue eyes carefully followed the Quaffle, and when it began to fall, he shot forward with the intent of grasping it before she did, and he'd had a grasp on it, but that didn't stop Artemis from all but yanking it from his grasp.
He swore quietly, and as Artemis rose, Louis had time to push forward a bit and turn that way, catching up with Artemis and flying expertly beside her, and his attempts to take the Quaffle from her grasp were futile.
The only real way was to let her attempt to score, and try to block it, or take her off course. He wasn't much as of Keeper, so Louis dropped under her and raced forward, then-almost as she had, curved his broomstick up, right in front of her, and dislodged her course sharply.