Airing at 9pm, 'A Lion Roars' - which saw Kirsty and Warren come to blows - pulled in a solid 6.01m (25.6%).
There were also strong performances on the channel from The Magicians and In It To Win It, which grabbed 5.7m (25%) and 6.6m (28.1%) at 7.15pm and 8.15pm. Prior to that, All New Total Wipeout entertained 4.17m (18.9%).
Over on ITV1, live FA Cup coverage drew 5.12m (25.8%) between 4.45pm and 7.15pm. The latest Primeval scored just 3.39m (14.8%), and 4.08m (17.2%) watched Take Me Out an hour later, before a repeat of Benidorm amused 2.62m (11.9%).
Channel 4's screening of Fantastic Four took 1.7m (7.4%) between 7.15pm and 9pm and 213k (0.9%) on timeshift, after which The Million Pound Drop Live entertained 2.25m (9.8%) as well as 243k (1.1%) on timeshift.
Elsewhere, a repeat of Dad's Army secured BBC Two's highest audience of the night, with 2.87m (12.5%). Documentary From Haiti's Ashes interested 1.05m (4.5%) at 8pm, then QI XL had 1.86m (7.9%), and The Tudors mustered 1.65m (7.7%) at 9.45pm.
Meanwhile, a double bill of NCIS nabbed 877k (3.9%) and 1.23m (5.2%) for Channel 5 at 7pm and 8pm, before CSI: Miami and CSI: NY logged 1.19m (5%) and 2m (9.5%).
Overall, BBC One owned primetime with 23.1%, significantly ahead of ITV1's 15.7%. Channel 4 finished third with 8.1% (+1: 1%), followed by BBC Two with 7.7%, and Channel 5 with 5.8%.
BARB ratings data supplied by Attentional