Some 10m viewers (43%) saw Kitty Brucknell clash with rival Honey in what Louis Walsh dubbed the most "brutal" Boot Camp ever.
A further 299k (1.4%) watched Curtis Ray White fight the axe on ITV+1, and The Xtra Factor nabbed 1.11m (5.5%) on ITV2 for the largest multichannel audience of the evening.
Following the main terrestrial X Factor epsiode, The Jonathan Ross Show nabbed 2.94m (14.8%) from 9.30pm, as well as a further 134k (0.9%) on timeshift.
In a ratings clash that has seen intense debate, the light family fare of All Star Family Fortunes once again beat competition from BBC One's original drama Doctor Who. The ITV show took 5.54m (26.5%), while the Matt Smith-fronted sci-fi interested 5.25m (24.6%).
Elsewhere on BBC One, The National Lottery: Secret Fortune (7.55pm), Casualty (8.45pm) and Live At The Apollo (9.35pm) attracted audiences of 3.69m (16.2%), 3.82m (16.3%) and 2.26m (11%) respectively.
On sister channel BBC Two, one-off documentary The 1951 Festival of Britain: Brave New World informed 1.55m (6.6%) at 8.15pm, and QI XL increased the audience to 1.81m (8.3%) an hour later.
Dambusters: Building the Bouncing Bomb educated just 550k (2.4%) on Channel 4 in the two hours from 7.15pm before The Million Pound Drop rescued the evening with 1.61m (8.4%), as well as 247k (1.8%) on timeshift.
Big Brother stayed above the million mark on Channel 5 with 1.09m (5.4%), prior to which 613k (2.6%) tuned in for CSI: Miami.
ITV1 dominated the primetime share with 28.9%, putting BBC One in the shade with 18.4%. BBC Two, Channel 4 and Channel 5 followed with 7.5%, 4.5% and 3.9% respectively.
BARB ratings data supplied by Attentional