With NCAA men’s basketball coverage expanding to four networks this year, CBS’ and Turner’s second-round coverage of the 2011 NCAA Division I Men’s Basketball Championship on TBS, CBS, TNT and truTV last night combined to deliver the highest rating for the first Thursday of the NCAA Tournament since 1991. Switching to all-live coverage on TBS, CBS, TNT and truTV in four windows, the games drew a combined 5.7/13 overnight household rating, up 24% from the 4.6/11 for CBS Sports’ 2010 coverage, in which the network switched back and forth between games.

The first telecast window of the day (12:00 NOON-4:15 PM, ET) earned a 4.4/15, up 42% from last year. The second window (3:00-6:45 PM, ET) delivered a 5.1/13, up 46%. The third telecast window (7:00-9:45 PM, ET) delivered a 6.5/12, up 8%, and the final window of the day (9:15 PM-12:30 AM, ET) earned a 6.9/13, up 13%.