Bumbry's two-out, two-strike, bases-loaded single in the bottom of the 12th inning gave the Baltimore Orioles a 2-1 victory over the Chicago White Sox tonight and Manager Earl Weaver a pleasant 49th birthday present.

Bumbry's hit -- only the Orioles' third for the game -- brought to an end the 3 hour 14 minute nail-biting pitching duel between starters Steve Stone and Richard Wortham before a crowd of 15,518.

Neither pitcher was around to finish the game, however. Oriole releiver Tippy Martinez gained his eighth win against two defeats while Chicago reliever Ed Farmer fell to 2-4.

Baltimore retained its five-game lead over the Boston Red Sox, who powered their way to a 12-1 win over Minnesota.

Martinez's two-inning performance was icing on Weaver's birthday cake. Martinez has allowed two runs in his last 23 innings spanning 10 games.

Overshadowed was the remarkable performance on "Tex" Wortham (12-11), who lasted nine innings and gave up only two hits while striking out five. He threw only 99 pitches, one of which Lee May hit for a single in the second inning and another which Eddie Murray put into the seats in the eighth for his 17th home run.

The Orioles had lost five of their last seven before tonight's victory. They seemed destined to continue their slump when White Sox second baseman Jim Morrison, a .215 hitter, slammed his fifth home run, into the first row of the left field bleachers, in the sixth. It was the 24th home run hit off Stone this season.

Stone then settled down to retire 10 in a row before yielding a single to his former teammates in the 10th.

He has not had a victory since one-hitting Milwaukee on July 30 and wanted to stay in.

"But when Earl gets it in his mind to pull a pitcher," he said, "you know you're gone."

"We have the best bullpen in baseball," Stone added, "so at least I don't feel as bad when I have to leave the game because everything is in good hands."

Weaver also shook up his batting order tonight. Kiko Garcia and Gary Roenicke hit one-two, Ken Singleton his usual third, May fourth, Benny Ayala fifth and Murray was moved back to the sixth spot.

The new lineup did not bother Wortham as he pitched his second two-hitter in a row. He gave up only one run while beating New York Thursday.

Bumbry wasn't even in Weaver's starting lineup as he took a rest in favor of Roenicke, who made two errors in center field. One turned a routine single by Alan Bannister into a triple.

Bumbry was thrown out by White Sox catcher Milt May on a topper in front of the plate to close out the 10th when he pinch hit for Ayala.

He did better two innings later after Farmer had walked pinch hitter. Pat Kelly and Garcia on 11 pitches, and passed Singleton intentionally after pinch hitter Terry Crowley's deep fly to left had advanced the runners.

This time Bumbry waited on a curve ball from Farmer and stroked it over shortstop Gregg Pryor's head into left center.

"I've been around for awhile," said Bumbry. "I was waiting for him to hang that curve ball. We had been out there for 12 innings. I would have felt bad if I didn't get the hit. The game had gone on long enough.

"Considering the way we've hit the ball the last two nights, we were fortunate to win this one. That says a lot about our pitching staff."

His blast came against a firm, gusty wind blowing over the center field wall that had prevented home runs an inning earlier by Singleton and May, who both drove Chet Lemon back to the left center field wall to pull in deep fly balls.

The Sox mounted their best threat in the 11th when Squires blooped a single to left and Lemon followed with a single to left-center. But Roenicke atoned for his previous sins by cutting down Lemon at second base when he tried to stretch his hit into a double.