User blog comment:Tutles/Episode 117: Thunder Crashes Review/@comment-2106167-20120211114129/@comment-3987368-20120211133751

GM, She couldn't beat him at the moment, as you admit. The Lachrima was implanted in him when he was a child, barely any older (if at all) than Erza when she got hers. She was two years younger than Laxus when she became but we know that age isn't a factor in becoming an S-Class, it's dependent on when the master lets you take the exams. Given Laxus' rebellious nature, it's likely the master held him back. His simple muscle mass and ability to use thunder in conjunction with melee puts him well ahead of her as well.