Brendan O'Carroll's BAFTA award-winning Irish sitcom climbed to 7.27 million (27.6%), while the Miranda Hart comedy took an ample 7.11m (26.6%).
Both airing in the 9pm hour, the higher audience for Mrs Brown's Boys is all the more surprising given the show's 9.30pm slot, with BBC One handing Miranda the more prestigious 9pm slot.
With Panorama still off air, another evening appearance for Rip-Off Britain was watched by 3.44m (13.4%) at 8.30pm, while EastEnders performed well at 8pm.
Meanwhile, Lewis remained a popular alternative for viewers as the potentially-final run of the ITV detective spinoff continued with 6.12m (23%), adding 403,000 on +1.
Bosses will be pleased as the network's rebrand brought with it Coronation Street's highest audience of the year so far, which boosted Cornwall with Caroline Quentin to 4.13m (16.1%) at 8pm (+1: 101k).
Over on BBC Two, Winterwatch debuted with a promising 2.3m (8.8%) at 8.30pm, bolstered by University Challenge's 3.28m (12.8%) at 8pm.
Elsewhere, Celebrity Big Brother logged 1.96m (7.4%) for Channel 5 at 9pm (+1: 270k), beating Embarrassing Fat Bodies which appealed to 1.59m (6%) at the same time on Channel 4 (+1: 308k).
Then in the 10pm hour, What Happens in Kavos attracted 1.57m (8.7%) to 4 (+1: 285k), while 1.11m (6%) watched Botched Up Bodies as well as 108k on timeshift.
Overall, ITV won primetime with 25% (+1: 0.9%) above BBC One's 22.8%. BBC Two claimed third place with 7.2%, ahead of Channel 4's 5.1% (+1: 0.7%), and Channel 5's 4.6% (+1: 0.4%).
BBC Four's popular quiz show Only Connect topped the multichannel ratings with an impressive 1.02m (4%).
BARB ratings data supplied by Attentional