5.2 million people in the UK watched Into the Dalek, a share of 24.7% of the total TV audience, according to unofficial overnight viewing figures.
Doctor Who was the second-highest rated programme of the night, which was won by the return of the talent show The X Factor on ITV, which had 9.3 million watching. Against the Doctor, The Chase: Celebrity Special had an audience of 4.2 million.
Episode two of the new series of Doctor Who did not suffer any loss of viewers during the clash with The X Factor, with ratings stable throughout the episode. Around 2 million viewers switched to ITV as Doctor Who finished. The second-highest rated programme on BBC One was Casualty with 3.9 million watching.
Doctor Who is currently 21st for the week. Final figures will be released next week.