BBC One's flagship crime drama, which has been plagued by a feud between cast and writers over its quality, kicked off its ninth series with 7.77m (31.6%).
Though down half a million on 2011's July opener, the long-running series was unrivalled in its 9pm slot, despite inheriting only a tiny audience of 2.21m (9.3%) for a One Show special at 8.30pm.
Later on in BBC One's schedule, new family sitcom Citizen Khan launched with an impressive 3.41m (20.9%) at 10.35pm.
Meanwhile on ITV1, Prince Harry's Mountain Heroes could only muster 2.16m (9.4%) in the 9pm hour, in spite of a strong Coronation Street lead-in.
Over on BBC Two, University Challenge quizzed 2.46m (10.5%) at 8pm, Lorraine's Fast, Fresh and Easy Food served up 1.56m (6.6%) at 8.30pm, and Horizon interested 1.54m (6.2%) at 9pm.
Frankie Boyle's Channel 4 special The Boyle Variety Performance amused 898k (5.5%) at 10pm (+1: 135k/1.5%), prior to which 1.16m (4.7%) caught Alan Carr: Spexy Beast (+1: 305k/1.7%). The Restoration Man had 1.1m (4.6%) at 8pm (+1: 154k/0.6%).
Overall, BBC One topped primetime with 24.5%, beating ITV1's lacklustre 18.5% (+1: 0.5%). BBC Two earned third place with 6%, ahead of Channel 5's 5% (+1: 0.3%), and Channel 4's 4.2% (+1: 0.8%).
BBC Four quiz show Only Connect restarted with a hefty 905k (3.8%), topping the multichannel ratings for the night. Charlie Brooker's A Touch of Cloth concluded with 384k (1.6%) on Sky1, down on Sunday's premiere.
BARB ratings data supplied by Attentional