The game plan the Harvard men's basketball team designed for Saturday's showdown with Army worked perfectly.

The thing is, the Cadets were the ones who used it.

Running a patient, ball control offense and a tightly knit zone defense, Army embarrassed a visiting Harvard squad, 73-49, before 1000 at the Army Field House in West Point, N.Y. What the Cadets did was totally thrash a Crimson squad that played its poorest ball of the still-young season.

"We didn't execute anything we wanted to," said Crimson forward Joe Carrabino, who the Cadets held in closer check gone AWOL. "And they executed everything we did want to."

Which included a strong rebounding game, a slowed-down offense and a defense that wouldn't let anyone in a foreign uniform get past it.

"We went in with a game plan," said sharpshooting junior guard Bob Ferry, who finished as the Crimson's high scorer with 10 points, "and just didn't follow it at all."

It became a little hard to follow after the Cadets used two eight-point spurts in the first 13 minutes to jump to an early 22-10 lead. "After they got a lead they became a much better team," Harvard Captain Ken Plutnicki said yesterday, "and as a result, we had to scrap the game plan."

And that's where it all fell in.

Considered by many the finest Harvard team in several years, the only signs of such quality came in the game's first few moments, when the cager held a slim 6-4 advantage. After that, the hosts put an old-fashioned military shipping on the visitors.

Forced into mistake after mistake in the opening half's waning minutes, Harvard found itself on the short end of a 32-24 halftime score. "We lacked a little patience on offense," said Carrabino, explaining the momentary collapse of a Harvard team that had dominated both its opponents in its first two games. "We didn't control the ball as we should have, and they made the most of that in the first half."

What the Cadets did in the second half was quickly put the game out of any reach. A run of 10 straight points--thanks to some nifty field goals (Army shot 59 percent from the field)--early in the period put the game on ice.

Harvard's atrocious 38 percent in field goal competitions only slipped as Crimson Coach Frank McLaughlin went to his bench once Army had all but secured its third victory in four games this year.

With most Crimson starters riding the bench for the last 10 minutes and most Army starters riding the Crimson subs, it didn't take long for the Cadets to reach their 24-point victory margin.

At West Paint H.V.

Army (73)--Schwarz 0-0-10- Miltron 0-1-1 Michaslan 0-0-0; Houston 7-4-18; Cozzens 8-4-20; Yeager 4-0-8' Belanger 1-0-2; Popovich 1-0-2; O'Donnel 2-1-5; Ryscavage 0-1-1; Appleman 0-0-0; Ellia 0-0-0; Steptoe 0-0-0; McGuinness 0-0-0; Totals 32-11-73.

Harvard (49)--Plufniclo 3-2-8l; Wlides 2-0-24; Carrabino 2-5-9; Smith 1-4-6; Ferry 4-2-10; Duncan 2-0-4; Trout 0-2-2; Webster 1-0-2; Boyle 0-0-0; Standley 1-0-2; Daugherty 0-0-0; Danierson 0-1-1; Fariey 0-1-1; Simbeck 0-0-0; Parkarbon 0-0-0; Totals 16-17-49.