For all of the debate about who should be ranked No. 1 among the three undefeated, power-conference teams, the far greater challenge right now when filling out a ballot is ranking the teams with one loss.

There are 15 once-beaten teams in this week's AP Top 25, and eight or nine of them could probably make a legitimate claim to being No. 4. That number of one-loss teams is sure to dwindle in the next few weeks, but there's still a good chance that the selection committee will face the difficult decision of which two or three of those teams to put into the playoff.

Obviously, there's much more to any team's résumé than a single loss, but if the BCS era is an indicator, the nature of that loss could become a major topic of discussion when distinguishing among the once-beaten teams. Perhaps that's because in a sport where there is so little common ground on which to compare top teams, having exactly one loss is the trait they all share.

So, recognizing that this could be a factor in determining which teams get into the playoff, here are the best and worst losses by current Top 25 teams that have only one defeat. The losses are ranked by Game Score, which is a metric developed by ESPN Stats & Information that takes into account quality of the opponent, location of the game, flow of the game and final score. It's important to note that opponent quality adjusts as more games are played, so these Game Scores will also change from week-to-week. (All Game Scores can be seen by clicking team links on the FPI page.)