The Baltimore Orioles dug themselves a big hole tonight-but climbed out to record one of those memoralbe victories the 16,249 folks in attendance will be reliving over crabs and beer for a long time.

Al Bumbry's two-run, two -out single climaxed a three-run ninth-inning rally that forced the hated New York Yankees into extra innings. Then Rick Dempsey's Two-out single in the 10th won it for Baltimore, 6-5.

The Yankees will be talking about that 10th inning for awhile, particularly third baseman Craig Nettles and catcher Thurman Munson.

Ken Singleton started the winning rally off Rich Gossage with a bouncer up the middle for his third hit. John Lowenstein was enlisted as a pinch runner and, after Eddie Murray had filed out to Mickey Rivers in right center, Lowenstein broke for second on a pitch to Doug DeCinces.

Munson's throw on the steal attempt skipped over second baseman Willie Ransdolph's glove into center field and Lowenstein kept on running. But he seemingly hadn't reached third when Rivers' throw took a short hop into Nettles' glove. Umpire Bob Roesner delayed his call, apparently to see if Nettles held the ball, which he did, and then signaled safe.

Lowenstein was the principal figure in a atrocious call by another amateur umpire Tuesday, when he overran second and was called out, although the replay showed him clearly safe. This time the reply was not conclusive, but i indicated Lwoenstein had probably come out even.

"Let's just say it was closer than last night," Lowenstein said. "The last two nights would have made a great cartoon."

New York Manager Bob Lemon, after chasing Roesner down the left-field line, ordered intentional walks to Doug Decinces and Pat Kelly. On a 1-0 pitch on Kelly, Munson needed to make a leaping catch to avoid a game-ending wild pitch. On 3-0, Gossage came so close to the plate that Kelly started to swing, then checked it.

Lemon called for Paul Mirabella, who retireed Larry Harlow on a fly to short left. Lowenstein stayed put, although second guessers in the stands were disturbed when Jay Johnstone's throw was far off target.

"Obviously, I could have made it," Lowenstein said. "But hindsight is great. That was hit so short I never gave a thought to running."

It didn't matter, because Dick Tidrow came in and Dempsey reached out and blooped a 1-2 pitch over second base to send the Orioles' fans home happy for the first time in the last five meetings with New york.

Yankee starter Ed Figueron cruised into the ninth with a 5-2 lead, and a four-hitter, the last safe blow being Lee May's one-out single in the fourth.

As fans streamed toward their cars. DeCinces walked on a 3-2 pitch and Kelly lined a shot off the mound into center field. DeCinces unwisely tried to reach third and would have been out, but Nettles was 10 feet from the bag when he fielded Rivers' throw and missed the tag.

May grounded a single into left and Gossage replaced Figueroa. Dempsey twice bunted foul trying to advance the trying runs to second and third; then, on a 2-2 offering Gossage accomplished that assignatment with a wild pitch.

Gossage snard Dempsey's hard grounder and pinch hitter Terry Crowley flied to Johnstone, which left matters to Bumbry. Lemon, after talking to Gossage, retreated to watch Bumbry slice a line drive that fell a half step in front of the racing Johnstone in short left, Kelly and pinch runner Terry Harlow sprinting home.

The Orioles had seemingly blown this one in the fourth inning, when consecutive errors by second baseman Rich Dauer and first baseman Eddie Murray contributed to a three-run inning against Jum Palmer.

Chris Chambliss shattered the 2-2 tie with a line homer just inside the foul pole in right. Then Jim Spencer's routine grounder caromed off Dauer's knee.

Spencer, from nearby Linthicum, Md., continued to lead a charmed life as Johnstone grounced to Murray, two steps off first base. Murray went for the force and his throw struck Spencer's helmet, bounding into left field as the usnners reached second and third. It was Murray's first error in 80 games.

Bothe men scored on Bucky Dent's single to right and the game settled into routine-untile the Orioles once again proved that a guy who pays his money shouldn't go home until the last man is out. CAPTION: Picture, Oriole Eddie Murray is safe at home as Yankee catcher Thurman Munson reaches for late throw from second base. AP