The Cats (6-2) got off to such a quick start in this one, jumping in front 11-0, that Alton (6-3) was forced to play from behind all evening.
Dylan Dennis (21 points) hit the game's first hoop for Thayer, followed quickly by one from Ricky Smith (11 points).
Then, Austin Henry got hot.
He hit seven straight points for the Cats, and put in 13 of his 20 points in the first period.
Jordan Campbell (six points) stopped Thayer's run with the first of the Comets' eight 3-balls in the game, but the Bobcats responded with 11 unanswered points to move on top 22-3.
Dusty Chester (four points), Skyler Chronister (25 points) and Quaid Turner all dropped in hoops for Alton, but the Comets still trailed 29-9 deep in the first.
Chronister and Kalon Honeycutt made sure Alton closed the first on a positive note by firing in a pair of treys, but the Comets were in a 31-15 hole after one.
Honeycutt scored six points for Alton before exiting the game late in the third with an apparent arm injury.
While the first period was played at a breakneck, up-and-down pace, the second period was anything but that.
Alton scored just three points in the second -- on a free throw from Chronister and hoop by Wes Carswell (four points) -- while Thayer could muster only six points in the frame, leaving the Bobcats on top 37-18 at intermission.
Alton made its biggest push of the night midway into the third.
Fueled by nine points from Chronister, Alton closed the third on a 14-6 run, but stilled trailed 52-36 after three.
Chroinster shook free long enough to sink back-to-back treys in the fourth, but Thayer had built such a big lead early that the Bobcats ended up winning 73-52.
Levi Hargrove finished with 16 points for Thayer, with Brandon Childers adding three and Jacob Foley two.
Channing Burd tallied three points for Alton, while Levi Schmidt added two.
In a two-period junior varsity contest to start the evening, Alton jumped in front 18-0, en route to a 34-14 victory over the Bobcat JV squad.