The Victoria Coren-fronted lateral thinking game averaged an audience of 944,000 and a share of 3.9% in its 8.30pm slot.
Crowned the best-rated multichannel broadcast for a third week in a row, Only Connect is now BBC Four's most popular programme.
Elsewhere, New Tricks held a dominant 7.02m (29.7%) in the 9pm hour when faced with the return of a popular ITV series - the second series of Monroe launched with 3.08m (13%) and 241k (1.4%) on +1 - way below the James Nesbitt drama's 5.9m premiere rating of last year.
Paul O'Grady's For The Love of Dogs continued to please as it reached its penultimate week, pulling in 4.66m (19.4%) in a difficult 8pm slot opposite EastEnders, and 333k (1.4%) on ITV1 +1.
Nigella Lawson's Nigellisima served up 2.21m (9.2%) on BBC Two at 8.30pm, prior to which University Challenge interested 2.85m (11.9%).
Channel 4's highest rating programme was 999: What's Your Emergency, which drew 1.99m (8.4%) at 9pm, and 364k (2.2%) on timeshift an hour later.
Meanwhile, Classic Car Rescue anchored Channel 5's schedule with 1.02m (4.2%) in the 8pm hour.
Overall, BBC One held onto its primetime lead over ITV1 with 22.9% versus 22.6% (+1: 0.9%). BBC Two claimed third place with 6.8%, ahead of Channel 4's 5.4% (+1: 0.9%), and Channel 5's 3.9% (+1: 0.1%).
BARB ratings data supplied by Attentional