With Jennifer Hudson performing, Idol averaged 15.3m and an 18-49 adult demo score of 4.2, up 30% week-on-week for an episode which saw no act eliminated.
American Idol's strength helped Touch maintain viewers, with the latest edition drawing 8.2m (2.3) at 9pm.
Elsewhere, a Big Bang Theory (10.3m/3.0) repeat topped the 9pm hour, overpowering Grey's Anatomy (8.8m/2.9) on ABC.
An 8pm rerun of the Jim Parsons sitcom also beat the Alphabet Network's Missing (7.9m/1.4).
Rules of Engagement showed incredible resilience, averaging 8.5m (2.7) despite being surrounded by Big Bang Theory reruns on the Tiffany Network.
Meanwhile, NBC's new instalments of Community (3.2m/1.4) and 30 Rock (3m/1.4) picked up a few extra viewers in the 8pm hour, then 4.4m (2.1) tuned in to The Office.
At 9.30pm, the season finale of Up All Night logged 3.2m (1.5). Awake followed with just 2.7m (0.9).