A sore-armed relief pitcher and a millionaire hitter have moved the Pittsburgh Pirates within one victory of a spot in the World Series.

This morning Don Robinson couldn't raise his arm overhead. This afternoon he threw baseballs so hard the Cincinnati Reds couldn't hit them.

The Pirates pay Dave Parker maybe $800,000 a year to hit baseballs. He is a bargain. Today he diftly stroked a single to the opposite field in the 10th inning to drive in the winning run in a 3-2 victory over the Reds.

Now up two games to none in the best-of-five series for the National League championship, the Pirates go home for the third game Friday afternoon. They will start right-hander Bert Blyleven (12-5) against Cincinnati right-hander Mike LaCoss (14-8). History suggests the series is over, for never in a decade of playoffs has any team won a championship after losing the first two games.

Not only does history suggest the end is near; so does the way the Reds are hitting. They aren't. Twice now the Reds' pitchers have held the mighty Pittsburgh offense to two runs in the first nine innings. All that work gained only extra innings, with the Pirates winning the first game on Willie Stargell's 11th-inning home run and winning the second on Parker's screamer to left.

Until the ninth inning today, when the Reds scored a run to tie the game at 2, they had gone 15 innings against Pittsburgh with only eight hits and a single run.

"Our only strategy is to wake up a few bats," said John McNamara, the manager. "We have been in a slumber since mid-September."

And any time the Reds appear to be rousing themselves, here comes another Pittsburgh relief pitcher throwing sleeping pills at them. The Pirates' manager, Chuck Tanner, used five pitchers in the first game and sent six to work today, the last being the best, Don Robinson.

The Reds had tied the game in the last of the ninth and were one hit away from winning it. Against the Pirates' workaholic reliever, Kent Tekulve, who in 92 appearances earned 31 saves this season, the Reds suddenly struck consecutive doubles -- only the third time in 20 innings they had back-to-back hits.

Dave Collins' double drove in Hector Cruz with the tying run. Te

Dave Collins' double drove in Hector Cruz with the tying run. Tekulve was taken out, replaced by Dave Roberts, who promptly walked Joe Morgan. Now the Redshad men on first and second, one out, and needed any kind of single to win for the 55,000 customers who came to Riverfront Stadium on a beautiful baseball day.

What more could the Reds ask than to have their Nos. 3 and 4 hitters at the plate in this situation? If Dave Concepcion didn't win it, George Foster could.

Don Robinson had other ideas. Beset by shoulder pain all season, the 1978 rookie pitcher of the year had finished up the opener by striking out Ray Knight with the bases loaded to save the 5-2 victory. This morning, just from the effort of working to two hitters, Robinson said, his shoulder was so still he couldn't raise his arm freely.

"I was going to challenge Concepcion," Robinson said. That meant he would throw his considerable fast ball to a hitter who loves to hit fast balls.

Strike one swinging. Strike two swinging. Fast balls, both.

"Then I threw him a curve ball that nobody in the world could have hit," Robinson said.

Strike three, with Concepcion lunging after a curve ball low and outside.

"Then I wanted to keep it inside to Foster," Robinson said.

That is because Foster, if given a fast ball on the outside part of the plate, can cause the ball to disapper 400 feet away.

On the first pitch, a fast ball inside, Foster weakly grounded out to the second baseman. The Reds' offense, awake for about 36 seconds, pulled the covers up to its chin for the night. In the 10th, Robinson put the Reds down 1-2-3, no one even threatening to hit the ball hard.

In that 10th inning, Robinson was protecting the 3-2 lead produced by Parker.

After Omar Moreno led off with a single against reliever Doug Bair and was bunted to second, that brought up Parker. At 6 feet 5 and 230 pounds, Parker may be the best big-man hitter ever (23 home runs a year, a .320 average and two batting championships since 1975).

With the game in the balance, Parker guided a fast ball into left field for a single that drove in Moreno.

"Dave Parker plays every game like it's the last one of his life," Tanner said.

"I give it 110 percent every day so I can go home and sleep at night," Parker said.

Home, for Parker, is Cincinnati. He grew up here watching the Reds. "To get the game-winning hit here in front of mom and dad, my brothers and sisters, that's something special to me," he said.

Though the game came down to the classic confrontation of pitcher and hitter in extra innings, aficionados of what-might-have-been may be arguing into the winter that the Reds were robbed and Parker never should have had a chance to win it in the 10th.

That is because the Pirates scored a run, going ahead, 2-1, in the fifth, only after umpire Frank Pulli ruled that Cincinnati's right fielder, Collins, had trapped Phil Garner's line drive, not caught it.

On the run, Collins dove for Garner's shot and, after a somersault, held the ball high in an outfielder's traditional signal of a great catch. Pulli, meanwhile, was waving his arms in the "safe signal that meant the ball had been a base hit.

Collins argued with Pulli. Mcnamara argued that Pulli should ask a second opinion; Pulli said he didn't need to, he had seen the whole thing perfectly. "He trapped the ball and rolled over it," Pulli said.

With two out, Tim Foli lined a double down the third base line to drive in Garner.

"I caught it," Collins said later.

Not that it mattered much.

"That play didn't cost us the game," he said. "We had a lot of chances to win, but we need o,r Nos. 3-4-5 men to come through and we need me and to win, but we need our Nos. 3-4-5 men to come through and we need me and the Nos. 3-4-5 men -- Concepcion, Foster and Bench -- have driven in only two runs while failing in 11 at-bats to get a hit with men on scoring position.

Symbolic of the Reds' feeble offense, the first run scored today on a sacrifice fly out by the pitcher, Frank Pastore. Dan Driessen and Knight set up the run with singles in the second inning.

Pittsburgh tied it at 1-all in the fourth after successive singles by Foli, Parker and Stargell. The run came in on Bill Madlock's ground out.

Pastore and his opposite number, Jim Bibby, went seven strong innings apiece before a crick in his neck sent Bibby to the showers and McNamara pinch-hit for Pastore. From then on, the decision hung on what the teams did with relief pitchers, and when it mattered most, Robinson and Parker were better than anything the Reds could find.