In classical systems with 1.e4, the game often turns on whether white can plant a knight into enemy territory, often on d6 or f5. These are examples of what happens when white is able to do that.
Pillsbury vs Tarrasch, 1902 (C78) Ruy Lopez, 29 moves, 1-0
Teichmann vs Schlechter, 1911 (C90) Ruy Lopez, Closed, 25 moves, 1-0
Spassky vs J H Donner, 1966 (C86) Ruy Lopez, Worrall Attack, 35 moves, 1-0