AMC’s “The Walking Dead,” basic cable’s biggest series of all time, opened its fourth season Sunday with its biggest numbers yet.

Opposite intense and higher-rated sports competition this year from both football and postseason baseball, “Walking Dead” returned Sunday with an average audience of 16.1 million viewers. This is more than 5 million viewers better than last year’s 10.87 million and more than double where it kicked off its second season in October 2011 (7.26 million).

It also did a huge 8.2 rating in adults 18-49.

The previous series high for “Dead” was its third-season finale last spring, which drew 12.42 million and a 6.4 rating in adults 18-49.

By comparison, AMC’s “Breaking Bad” wrapped its run last month with an average audience of 10.28 million and a 5.3 demo rating — easily the best scores for the series.