Starring Benedict Cumberbatch, the five-part series kicked off with 3.13m (14.1%) on BBC Two in the 9pm hour, topping the slot for half an hour between 9pm and 9.30pm.
The Terrestrial Channel of the Year's killer 8pm hour combination of Mastermind (2.16m/10.3%) and Gardeners' World (2.44m/11.3%) boosted Parade End's chances.
Over on BBC One, In with the Flynns dipped to 2.71m (12.8%) in its new 9pm slot, but the audience rose to 4.02m (18.8%) half an hour later for a repeat of Mrs Brown's Boys.
8 Out of 10 Cats Does Countdown, featuring the likes of Jon Richardson playing Channel 4's famous word game, amused 1.39m (6.5%) at 9pm and 371k (2.1%) on +1 as the broadcaster's Funny Fortnight season reached its penultimate day.
Overall, BBC One topped primetime with 19.8%, above ITV1's 17.6% (+1: 0.6%). BBC Two comfortably earned third place with 9.3%, ahead of Channel 5's 5.4% (+1: 0.2%) and Channel 4's 4.1% (+1: 0.9%).
Digital channel Yesterday pulled in an unusually high 465k (2.2%) for its new series Great British Ghosts, which was broadcast in the competitive 9pm slot.
> Read Digital Spy's report on Friday's soap ratings here
BARB ratings data supplied by Attentional