Best response to the Petrov's Defense: Classical Attack (C42)

1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 · Black to move

What is the best response to the Petrov's Defense: Classical Attack (1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4)? Black to move. See the top replies ranked by opening theory and real-game results, starting with Nf6.

The main theoretical reply is Nf6, reaching the Petrov's Defense: Classical Attack, Closed Variation.

Ranked replies for Black