The E4 sitcom starring Johnny Galecki and Jim Parsons took a hefty 1.11m (4.8%) and 365k (1.6%) on +1, despite being slightly down on last week's 100th episode, with Celebrity Juice grabbing 1.75m (9%) on ITV2 from 10pm (+1: 303k/2.8%).
Elsewhere on E4, a brand new episode of Happy Endings entertained 261k (1.1%).
On the terrestrials, Long Lost Family won the 9pm hour with 4.86m (21.2%). An additional 289k (1.6%) saw it on timeshift.
On BBC One, Watchdog drew 4.38m (18.5%) from 8pm, with Out of Africa: Ivory Wars managing 2.26m (9.9%) afterwards.
Peter Kay Live at the Bolton Albert Halls appealed to 3.04m (13.3%) on Channel 4 (+1: 407k/2.3%). Earlier, Get Your House in Order was seen by 955k (4%) with 294k (1.3%) on +1.
From 10pm, Ricky Gervais's Derek was watched by 1.86m (9.2%) and 246k (2.1%) on timeshift.
BBC Two showed Natural World (1.67m/7%) and White Heat (1.16m/5.1%).
Channel 5's airing of The Perfect Storm attracted 721k (3.8%).
Overall, ITV1 won primetime with 21.9% (+1: 0.7%) ahead of BBC One's 18.1%. Channel 4's 7.2% (+1: 1.2%) beat BBC Two's 6.6%, while Channel 5's 2.9% (+1: 0.1%) staved off ITV2's 2.6% (+1: 0.3%) to hold on to fifth place.
BARB ratings data supplied by Attentional