Tom Courtenay received his first Oscar nomination for portraying Pasha Antipov/"Strelnikov" in Doctor Zhivago.
Tom Courtenay plays Pasha who at the beginning of the film is an idealistic revolutionary encouraging it through peaceful demonstration. He is also the sort of fiancee of Lara (Julie Christie). In his first scene Courtenay has the right honest earnestness in showing Pasha's belief in the Revolution, as well as in seeking his relationship with Lara. Courtenay has a great deal of genuine warmness and love he shows in this scene, which he appropriately establishes to rid out of Pasha later.
After his peaceful demonstration is ended by government troops violently Courtenay shows a changed Pasha when he meets Lara afterward injured from the attack. Courtenay is effective because he does not immediately show a completely different man yet. Courtenay shows that his earnestness has mostly been turned to anger, but that there still is a little of it left, and also that this anger is partially an instinctual reaction from the trauma of the attack.
In later scene for example when he runs into Laura who is going to attempts to kill Komarovsky (Rod Steiger). When he first runs into her there is still some of that love and earnestness left in him, so much that she helps her away after her attempt. Courtenay shows Pasha's old love for Lara is reduced greatly though by understanding that she had an affair with Komarovsky. In his silent scenes afterward there is coldness in the way he looks at her, only marrying her because of the love he once felt that has drifted very much away from him.
Except for a brief moment during World War I, he still shows the same earnestness of old when he leads the troops into battle. Afterward though Pasha shows up once more no longer Pasha, but calling himself Strelnikov. Courtenay is amazing in his single final scene where he shows how cold of a man Pasha has turned into. It works well because Courtenay indicated this change all the way through his performance beforehand, and what happened in the war is the appropriate cause for his final change into Strelnikov.
Courtenay is absolutely chilling in this final scene, and it is made especially effective because of the difference from the beginning to this scene. There is no warmness left in Courtenay's performance. There is only a hallow shell of a man, with only his violent mission left for himself. Courtenay is amazing here because he truly becomes a man who has loss any indication of his old self really, he shows there is nothing left in Pasha except for his hatred. His final scene fully realizes his whole portrait of the Pasha's fall, which Courtenay brilliantly worked toward throughout the entire performance.