The CBS sitcom averaged a season high of 14.7m (4.9), up 1.4m week-on-week, for an episode which saw Laurie Metcalf return as Sheldon's mother Mary.
After Big Bang Theory, Patrick Warburton comedy Rules of Engagement began its sixth run with 11.5m (3.7), its best premiere rating since 2007.
Capping a strong night for the Tiffany Network, Person of Interest and The Mentalist held steady with 12.3m (2.7) and 12.5m (2.5).
The Vampire Diaries logged 2.9m (1.3) for The CW in the 8pm hour, ahead of NBC's repeats of Community (2.5m/0.9) and Parks and Recreation (2.5m/1.1).
The Peacock Network took the lead at 9pm, as The Office (3.2m/1.5) and Whitney (2.6m/1.1) got the better of The Secret Circle (2.1m/0.9).
Elsewhere, ABC's recently cancelled Charlie's Angels rumbled on with 5.6m (2.1), then Grey's Anatomy drew 9.4m (3.5), and Private Practice mustered 6.6m (2.4) at 10pm.
Over on Fox, the second World Series game between the Rangers and Cardinals scored 12.9m (3.7).