The NCAA championship game on CBS drew a 17.1 overnight rating (the percentage of U.S. homes tuned in) and 27 share (the percentage of TVs in use at the time), according to the network and Turner Sports.
Those numbers are up 33% from last year's 12.9/21 when Connecticut beat Kentucky.
The last time a March Madness finale had preliminary ratings so high was back in 1997 (18/28), when defending champion Kentucky lost to Arizona in overtime.
This year's game was a thriller as well. After a halftime tie, Wisconsin claimed a nine-point lead only to be outscored by Duke, 29-15, in the final 13 minutes. Coach Mike Krzyzewski and the Blue Devils ended up claiming their fifth national title with a 68-63 victory.
The ratings must have come as great news to the network, which was probably concerned after undefeated Kentucky lost to Wisconsin in the national semifinals on Saturday.
Overnight ratings measure only the largest markets in the U.S. Final numbers will be released Tuesday afternoon.