ITV drama Victoria bowed out on Sunday night with 4.8 million viewers - its best overnight figures since the launch episode.
The lavish production, starring Jenna Coleman and Tom Hughes, is returning for a second series next year.
The final episode of series one was watched by 5.5 million people and took a 25% share of the audience. The number of viewers peaked at six million.
During the launch episode, the big-budget drama attracted 5.7 million viewers and 6.1 million at its peak.
Poldark was also broadcast at 9pm, on BBC1, and was watched by 4.9 million viewers - an audience share of 22%.
ITV's figures include catch-up on its plus one channel.
Strictly Come Dancing's results show - presented by Tess Daly and Claudia Winkleman - was broadcast on BBC1 from 7.15pm to 8pm and had a peak audience of 9.7 million viewers. It averaged nine million with a 41.1% audience share, giving it the best Sunday results so far for this series.
The X Factor, which went out at 8pm on ITV, was seen by 6.5 million viewers and had a 28% share, with a peak of 7.5 million viewers, making it the broadcaster's most-watched programme of the night.