Since the only reason this Fan Fic ever got a page of its own is its entry on the General Fan Fic CMOA page, it's only right that be the opening entry for this page: IchigoversusSaber. The entire scene, from Rider's battle with Saber, to Ichigo's fight with Lancer, to his intervention in what would have become Rider's canon death. He does this last bit with a Getsuga Tensho powerful enough to rival Excalibur. Again: Ichigo matches Saber. In a Beam-O-War. While she is using her last resort and greatest weapon. Then, Ichigo defends against an onslaught of arrows from Archer like he did Senbonzakura Kageyoshi's blades when fighting Byakuya.
On their first night in Fuyuki, Ichigo gets attacked by Lancer. His combat instincts let him dodge a sneak attack, and even in his body Ichigo is only mostly helpless against a Servant. Then, he accidentally summons his own Servant, who holds off Lancer until Ichigo can get out of his body and show off his immense power.
From a different perspective, Sakura's Summoning Ritual gets hijacked by a tornado of power from someone with a Power Level so huge Zouken is concerned by it and can't even blame Sakura for failing; the other person's power is just that much greater.
Ichigo versus Berserker. Ichigo's raw spiritual power in Shinigami form is enough to counter The DreadedJuggernaut of Fate/Stay Night with little effort.note Don't worry, though, he doesn't just curb-stomp everyone; only Berserker, who's nothing but raw force.