Doctor Who: 10 Defining Tenth Doctor Moments
9. I Believe In Her (The Satan Pit)
"Except that implies - in this big grand scheme of Gods and Devils - that she's just a victim. But I've seen a lot of this universe. I've seen fake gods and bad gods and demi gods and would-be gods - out of all that - out of that whole pantheon - if I believe in one thing... just one thing... I believe in her."
The Doctor faces down the Devil. To be honest, that should make for a pretty memorable scene no matter how it goes down. It did go down, however, with the Doctor confronting the body of the Beast but not it's mind. Even if any potential battle of wits was lost, the Doctor's monologue more than made up for it.
It's a really strong speech and showcases a wide range of David Tennant's talents. It's a joy to watch as he goes from intimidated to intrigued to jubilant at figurng out the Beast's plan. Then he comes to a stop as he realises that stopping the Beast would risk Rose's before becoming utterly defiant with a poweful end to the monlogue. It's a really versatile performance, and deserving of it's place here.