You might think an unranked team (say, Oregon State) pulling an upset of the nations’ top-ranked team (say, USC) would be a rarity.

Turns out, it’s been done nine times in the past 20 years, so it’s not an event quite as rare as Halley’s Comet.

Here is a link to the list of unrankeds over top-rankeds, posted on the espn.com site and compiled by the sports information director at Arizona State.

Two notes on the list:

1. USC narrowly missed being on their twice … in less than a year. The Trojans were No. 2 a year ago when 41-point underdog Stanford defeated them at the Coliseum. But they had been No. 1 a week before; only a sloppy victory at Washington knocked them down to No. 2.

2. Somebody who commented on the list suggested that Arizona State’s 19-0 victory over top-ranked Nebraska, in 1996, was left off the list … isn’t dealing with all the facts. The score was 19-0, and Nebraska was top-ranked, and lost to ASU, but the Sun Devils were ranked No. 17 at the time (by USA Today; I’m not sure what the AP ranking was). They were a good team. Which is why I made the 320-mile (each way) drive to Tempe to see the game — and an upset considered, at the time, to be of gargantuan proportions.

Oh, a couple more thoughts …

3. The 2007 season often is recalled as the season of upsets, but if you look at the list you see three unrankeds over top-rankeds in 1990, alone. Notre Dame twice.

4. I didn’t see the UCLA game, the one they lost at home to Washington State (still inexplicable, really; UCLA’s greatest team, with Troy Aikman et al), but I remember listening to it on the radio as I was commuting somewhere. To another game? Into the office? I remember being appalled that it could happen, and remember thinking UCLA’s shot at a real national championship (in addition to that semi-shaky half-a-title from 1954) just went down the drain.