10-0 entering the Sugar Bowl; beat Alabama 24-23, then finished No. 1 in the final AP poll (taken after bowls) and was also named champion by FWAA and NFF.
Notre Dame’s 1973 schedule1973: 2 Champions, Zero Agreement
SPLITMULTIPLEAlabama and Notre Dame entered the Sugar Bowl both unbeaten and No. 1 in their respective final polls, but UPI voted before the bowl (naming Alabama) while AP, FWAA, and NFF voted after Notre Dame beat Alabama 24-23 in that game.
The case for each side
11-0 entering the Sugar Bowl, No. 1 in the final UPI coaches' poll, which by agreement with the AFCA was taken before bowl games that year; lost the Sugar Bowl to Notre Dame 23-24.
Alabama’s 1973 scheduleNo national title game was played after the 1973 season: before 1998 there was no mechanism to play one, which is why so many of these seasons were settled by vote instead.