I know there was some talk about there being no star performers in this edition of the World Cup, but for me, he's the one. He's not a spectacular, eye-catching type of player, but just goes about his work effectively. Bar the game against France, he has scored or assisted against every opponent Germany have played in this tournament (5 goals, 3 assists). He's 24 but looks 10 years older and is really whiny, but I'd gladly have him in my team. He gets things done.
Probably only James Rodriguez (6 goals, 2 assists) comes close to challenging him, but missing out on the later stages of the tournament means he's got fewer chances to shine. Brilliant World Cup by the youngster too.