Army is heading into the ECAC Basketball Tournament with a case of jitters. The Cadets won their 10th straight game yesterday, but what seemed like a one-sided battle became a war of attrition before Navy finally succumbed, 66-62.

The Mids were trailing, 53-36, with 7 1/2 minutes to play and gaps were beginning to appear in the packed granstand. Five minutes later the score was 60-58 and Navy was shooting for the tying basket.

Twice Navy's Kevin Sinnett slid underneath to shoot for the deadlock. The first time his shot spun off the rim. The second attempt was blocked by Clennie Brundidge.

Army then got things under control, hitting six straight free throws in one-and-one situations to keep the Mids at bay.

Although they hit 23 of 44 shots from the field, the Cadets managed only 20 of 32 at the line and the missed free throws helped bring Navy back to life.

The other ingredient was Sinnett, a 6-foot-6 junior who was controlled underneath by Brundidge in the first half. Sinnett scored 21 points after the intermission for a game-high total of 27, forcing his way inside to unload his shots despite heavy traffic.

"We tried to go to Kevin, particularly when Hank (Kuzma) fouled out (with 4:53 remaining)," said Navy Coach Bob Hamilton. "We weren't real active in the first half, but in the second half we played extremely well on offense. We moved and got the ball around.

"I knew we wouldn't quit, but I didn't know if we could come back against them on their own court. I'm proud of our guys. But I'm disappointed for the two seniors (Kuzma and Bob Scott). I don't like to lose anytime and I hate to lose the traditional game."

Navy had an early 13-6 lead, which melted to 23-21. Then the Mids endured a scoreless stretch of 8 minutes 17 seconds, extending into the second half, and Army was up by 35-23.

The score reached 46-27 before the Mids were able to chop a little off. At 49-36, Army tried a delay game and freed Brundidge and Pat Harris for uncontested layups. There wasn't the slightest indication that Navy was about to initiate one of the great comebacks of the college basketball season.

Sinnett sank two free throws and Army's Gary Winton was called for goaltending on Jack Stumborg's layup. While Winton and Harris failed on one-and-one tries, Kuzma converted a Scott assist, Stumborg downed a jump shot and Sinnett also sank a jumper. It was 53-46 and suddenly in doubt.

Two Sinnett free throws, a Sinnett layup and two jump shots by Stumborg helped the Mids inch closer, as Winton made only one of three free throws, failing to hit the rim on the third.

A Scott feed enabled Sinnett to make it 59-56 and, after the Cadets managed only one point on two one-and-one tries. Navy's Chuck Kuzma sank two free throws to reduce the deficit to two at 60-58.

Harris bounced a dribble off his knee to set up Navy's first opportunity to tie. He blew an open layup to present chance No. 2. There was no third.

Harris collected 12 assists in the first half, compared to one for the entire Navy team. In the second half, Army had just two assists, Navy 10.

Army Coach Mike Krzyzewski was able to celebrate his sixth victory over Navy without a loss -- three as a player from 1967-69 and three as a coach. Both he and Hamilton had to be restrained at times as they battled the officials for the tiniest concession.

"It's an emotional game for all of us." Hamilton said. "Of course, I'm caught up in all of them."

Army is tourney bound with an 18-7 record. Navy finished at 14-11, still its best record since 1962. Army Wins Winter Sports

A pin by Larry Kilhlstadius and superior decisions by Brian Rodgers and Nick Mygas paced navy to a 26-12 wrestling victory, its 13th straight over Army, at Annapolis yesterday.

Kihlstadius pinned Rob Forbes at 2:57 of the 142-pound bout to improve his record to 13-3-1. Navy finished at 8-11. Army at 6-11-1.

In other competition between the service academies:

At West Point, N.Y., Navy's fencing team came from behind to win, 14-13, and finish the season at 10-1 its best mark in 15 years. Trailing, 12-9, the Mids won five of their last six matches, capped by Tom Manobianco's 5-3 decision over Paul Johnson. It was Navy's fourth straight fencing win over Army, which finished at 7-6.

The Mids scored their eighth squash win in nine years over Army, 7-2, to finish the season at 10-5. Chet Seto paced Navy with a 3-0 victory over Dan Hammond.

Army countered with a 199.90-185.40 gymnastic victory. The Cadets, who have won the sport four straight years, were led by all-around performer Steve Meeki, 49.75 points, including a 9.25 score on the steel rings. Army finished at 8-2, Navy at 6-5.

In Annapolis, the Cadets took the rifle competition, 2,798-2,786. Bob Jacobs paced Army with a score of 569, get 2 add

Army's Rob Ruck won two swimming events and diver Kirk Schaumann won twice as the Cadets took the swimming competition, 64-49.

Army captured the winter competition from Navy this year, winning four of the seven sports.