The second Strictly performances show, which saw the girls taking to the dancefloor, averaged 8.59m (40.6%) for BBC One between 6.45pm and 8.05pm.
The X Factor's first day of 'boot camp' began an hour later, at 7.45pm, and ran for 90 minutes. It averaged 8.18m (36%) overall and peaked with 9.33m (41.4%) at 8.10pm, immediately after Strictly finished. The audience was variable throughout, however, and took its biggest hit at 9pm when a million viewers switched off before watching the final quarter hour.
In the 20 minutes that the two programmes were head-to-head, Strictly had 8.25m to X Factor's 7.27m.
On ITV1 in the 6pm hour, You've Been Framed! Family Special brought in 4.21m (25.1%), then at 7pm, All Star Family Fortunes had 4.22m (20.2%) over 45 minutes.
Post-Strictly, National Lottery Show Who Dares Wins picked up 4.95m (21.8%), then Casualty had a decent 5.42m (25.3%) until 9.45pm.
Channel 4's screening of the final Lord of the Rings movie in the trilogy picked up its highest audience yet. The Return of the King, screened between 7.30pm and 11.15pm, delivered a solid 1.95m (9.7%).
A new series of Timewatch began with 2.11m (9.3%) for BBC Two in the 8pm hour, then repeats of Have I Got News For You and Mock The Week pulled in audiences of 2.04m (9.4%) and 1.73m (8.5%) respectively.
The increased Saturday night competition slightly dented the audience for Five's US drama lineup. An NCIS double-bill brought in 0.81m (3.6%) and 1.05m (4.8%) from 7.50pm, then CSI had the channel's all-day high of 1.42m (7.6%). Law & Order: Criminal Intent put in 0.95m (7.3%) at 10.45pm.
Spinoff show The Xtra Factor topped the multichannel ratings tree, averaging 963,000 (5.4%) for ITV2 between 9.15pm and 10.15pm.
Sky Sports 1 had 911,000 and a massive 13.9% share for its coverage of Everton vs Liverpool between 12.30pm and 3pm, then Soccer Saturday kept 476,000 (6.2%) until 5.15pm.
> Click here to see last Saturday's ratings