The Channel 5 reality show drew 2.08m (10.4%) between 9pm and 11pm, peaking with around 2.5m as Clary's victory was announced by host Brian Dowling.
Denise Welch's January triumph was watched by a million more people in comparison.
Friday's final average was also lower than Jasmine Lennard's eviction rating on Wednesday, August 23. Emma Willis's Bit on the Side managed 873k (9%) at 10pm.
Channel 4's Paralympics coverage logged 2.42m (10.6%) between 7.30pm and 10.30pm, while ITV's live England qualifier between Moldova v England scored 3.98m (18.8%). Athletics aired on BBC Two from 7pm to an audience of 976k (4.9%).
Gardeners' World mustered 1.76m (7.9%) at 9pm, then 1.62m (7.8%) watched Parade's End.
A second chance to watch the premiere of Dallas was taken up by 683k (3.2%) on Channel 5 at 8pm.
Over on BBC One, a Miranda repeat took 4.16m (19.5%) at 8.30pm, then In with the Flynns amused 2.82m (12.7%), and Mrs Brown's Boys entertained 4.73m (21.3%) at 9.30pm.
Overall, BBC One topped primetime with 20.1%, ahead of ITV1's 16.7% (+1: 0.3%), Channel 4's 10.4% (+1: 0.4%), Channel 5's 6.6% (+1: 0.2%), and BBC Two's 6%.
BARB ratings data supplied by Attentional