Big Chef Takes On Little Chef, which sees the celebrated chef attempt to turn around the fortunes of the ailing restaurant chain, averaged 3.18m (13.1%) in the 9pm hour.
It was Channel 4's most-watched programme of the day, outranking traditional ratings winner Celebrity Big Brother. The daily BB highlights show - broadcast at the earlier time of 8pm - took just 1.7m (6.8%) for the hour, a new series low, however a sizable 513k (2.3%) watched Channel 4+1's 9pm repeat.
A second show, which featured the surprise eviction of Michelle Heaton, had a much more respectable 2.99m (16.5%) between 10pm and 10.50pm.
Channel 4's average primetime share rose more than two points to 9.5%.
After a solid start last week with 7.2m, Suranne Jones drama Unforgiven took a huge tumble in its second week. The latest episode pulled in 5.52m (22.6%) in the 9pm hour, outdoing the concluding half of BBC One's Hunter, which had 4.7m (19.2%).
The first visit to Coronation Street took 9.54m (39.8%) for ITV1 at 7.30pm, then a second episode managed 8.99m (35.5%) an hour later. EastEnders drew 9.11m (36.4%) for BBC One and 559k (3%) for BBC Three, while Emmerdale put in 7.91m (36%).
Hollyoaks logged 1.83m (8.7%) for Channel 4 and 656k (3.4%) for E4 - the best multichannel numbers of the day - while on Five, Neighbours had 1.55m (9.1%) and Home & Away had 1.05m (5.3%).
ITV1 still dominated primetime overall, but dropped from a share of 28.3% last week to 25.6%. BBC One was roughly even with 21.1%.
On BBC Two, the second quarter-final of University Challenge interested 3.16m (12.6%) at 8pm, then a new week of MasterChef began with 2.99m (11.9%) at 8.30pm. In the 9pm hour, the second episode of stock market reality show Million Dollar Traders appealed to 1.13m (4.6%). The channel's share was down to 6.6% in primetime.
Five was a distant fifth place for the night, but did improve its average share by half a point to 3.4%. Fifth Gear picked up 812k (3.2%) at 8pm, then documentary War Zone brought in 746k (3%). Action movie Cobra, starring former partners Sylvester Stallone and Brigitte Nielsen, kept 980k (6.9%) until 11.50pm.
Elsewhere, a double-bill of 24 attracted 474k (2.4%) to Sky1 from 9pm, a fall of around 150k on last week's premiere.
Ratings data supplied by Attentional