PITTSBURGH - Zach Duke knows what he isn't. That's what makes him what he is.

The 22-year-old left-hander broke into the big leagues with a bang this season, sporting an 8-2 record and 1.81 earned run average with the cellar-dwelling Pittsburgh Pirates.

"I know what I can and cannot do on the mound and stay very conscious not to stray from that," Duke said after Sunday's 3-1 season-ending win over Milwaukee.

"What I can't do is throw 97 or 98 miles per hour and blow my fastball past people. What I can do is throw to spots, hit the corners and not walk people."

What he does mostly is win.

Between Class AAA Indianapolis and the Pirates this year, Duke won 20 games and lost only five. He was 12-3 with a 2.92 ERA in 16 starts with Indianapolis.

He lost three starts because of a stint on the disabled list or he might have tied Dave Williams for the staff lead in wins with 10 - and Duke didn't make his major league debut until July 2.

In four seasons of professional baseball, Duke has won 51 games and lost only 19.

"You just don't see rookie pitchers come into this league and have that kind of success," said Pirates interim manager Pete Mackanin. "It's unfair, but you take it for granted Zach's going to give you a great outing."

Even in his two defeats, Duke was solid this season. He allowed one run in four innings against Cincinnati and two runs in five frames against Houston.

In his 14 starts with the Pirates, Duke allowed as many as four earned runs only once. He allowed one earned run or fewer 10 times.

Named National League Rookie Pitcher of the Month in July and August, Duke put together 26 consecutive shutout innings at one point.

"I'm not surprised by what he's done," rookie outfielder Nate McLouth said. "Zach has the right mental approach.

"When we were teammates in the minor leagues, he was consistent. Since he's been up here, he's been consistent. Nothing fazes the guy."

When Duke gets in trouble, he wriggles out of it. Milwaukee loaded the bases with none out in the first inning Sunday and managed just one run.

The leadoff batter reached base in three other innings against Duke and the Brewers had runners in scoring position with less than two outs in three other frames, only to come up scoreless."Zach's impressive even when he doesn't have his best stuff," Mackanin said. "He's constantly battling out there. He's very competitive and won't give in to any hitter."Duke threw 192innings between Class AAA and the major leagues this season. He threw 148innings between Class A Lynchburg and Class AA Altoona last year.He nearly made the Pirate roster out of spring training this season as a non-roster invitee."I'm a little tired and they don't want me throwing much in the off-season," Duke said. "I'll relax for a little while, then go to the instructional league to work on my bunting and a few fundamental things."This year was fun for me. It'll be nice to be able to take some time and reflect on it."One question remains: Can Duke pull off this consistency over an entire major league season?Stay tuned for 2006."When a team faces you for the first time, you're like a mystery man they have to figure out," Duke said. "The advantage definitely goes to the pitcher in that situation, as long as you throw strikes and keep the count in your favor."Hitters can adjust to pitchers, but pitchers can adjust to hitters, too. If I'm hitting my spots, I feel like I'm in control of the game."Duke could go into next season as the Pirates' Opening Day starter April 3 in Milwaukee."That would be exciting," he admitted. "But we'll see hat happens in spring training first."Mackanin hopes he's around in 2006 to see it."Just thinking about having that kid out there for a full season to see what he can do - that's a reason for optimism right there," the manager said.