As far as I can tell, this week's game at Oregon is the first time ASU has played a regular season game where both teams have been ranked in the AP top 10 at the time of the game.
Both Rose Bowl games featured top-10 matchups: ASU was #7 and Michigan #4 in the final regular season poll of 1986 and ASU was #2 and Ohio State #4 in the final regular season poll of 1996. The Fiesta Bowl following the 1975 regular season featured #7 ASU versus #6 Nebraska and there may be other Bowl games that I am overlooking.
However, I cannot recall a regular season game where both ASU and our opponent were in the top 10 at the time of the game. Anyone?
Updated 10/31: As best I can determine, this is the third regular season game where ASU and its opponent have both been in the top 10 at the time of the game. Both previous occasions have featured the Huskies. In 1982 ASU was ranked #3 when we played #7 UW, and in 1986 ASU was #7 and UW #6. Thanks to the AP Poll Archive and James Howell for providing great resources.