Rita Ora's stint on the panel in the show's second auditions show, airing between 7.45pm and 9pm, was seen by 8.4m (36.1%) and 475k (2.2%) on ITV1 +1.
Following the main programme, The Xtra Factor soared to 858k (4%) on ITV2, adding 133k (0.8%) on +1. But it was Film 4's Die Hard 4.0 screening that topped the multichannels with 889k (4.7%).
Simon Cowell's other Saturday night entertainment vehicle on ITV1, Red or Black?, also trickled upwards in the ratings - posting 3.42m (18.3%) at 7pm (+1: 106k/0.5%) and 3.7m (16.9%) at 9pm (+1: 177k/0.9%).
However, the increased momentum ended at 9.45pm, when The Jonathan Ross Show logged 2.52m (12.6%) and a further 208k (1.5%) on timeshift - as guests Suranne Jones, Ray Winstone and Jenson Button did not attract as many viewers as last week's lineup.
Meanwhile, BBC One had a fairly mediocre night in comparison, with Pirates of the Caribbean: The Curse of the Black Pearl (3.65m/18.9%) at 6.20pm, The National Lottery: Secret Fortune (3.56m/16%) at 8.30pm, Casualty (4.12m/19%) from 9.20pm, and Match of the Day (3.89m/27.5%) at 10.30pm.
BBC Two aired Dad's Army (2.29m/11.3%) and the BBC Proms (955k/4.4%), while Channel 4's 30 Greatest Comedy Shows pulled in 1.11m (5.5%), and Celebrity Big Brother took 1.32m (6.1%) for Channel 5 (+1: 128k/0.7%).
Overall, ITV1 posted a convincing primetime victory of 22.6% (+1: 1.3%) over BBC One's 19.2%. BBC Two claimed third place with 5.8%, ahead of Channel 5's 4.5% (+1: 0.3%), and Channel 4's 3.7% (+1: 0.5%).
