Matt Freed, Post-Gazette Chris Duffy steals second base, beating the tag from the Brewers' Tony Graffanino in the third inning last night. Click photo for larger image. Today Matchup: Pirates (Tom Gorzelanny 2-3) vs. Brewers (Doug Davis 8-6), 7:05 p.m. Where: PNC Park TV/Radio: FSN Pittsburgh/KDKA-AM (1020) and Pirates Radio Network. Related articles Bay's iron-man streak ends at 307 by strained hamstring Stats Geek: Double-threat Sanchez steady in the field, too Pirates Notebook: McLouth to disabled list, Davis promoted

Things must be going especially smoothly for the Pirates.

How else to explain a terrific emergency start from someone fresh off mopup duty?

Or the offense not missing a beat despite missing its linchpin for the first time in two years?

Or the leadoff man reaching base again and again and again?

Such is the current crescendo for the Pirates, who doubled up the Milwaukee Brewers, 4-2, last night at PNC Park to extend their winning streak to four.

"Another very good game," manager Jim Tracy said. "We picked up right where we left off on the weekend."

That was a three-game sweep of the first-place St. Louis Cardinals. While this opponent was not nearly as formidable, the victory might have been equally impressive in other ways.

Victor Santos, making his first start since June 15 because Shawn Chacon was unavailable, exceeded all reasonable expectations by limiting Milwaukee to two runs and five hits in his five innings. Not only was he rusty, but he also was coming off a miserable relief outing Wednesday in Houston, where he was tagged for four runs in 2 2/3 innings as part of a 14-1 laugher.

"I just wanted to keep the ball down, go right at 'em with my fastball," Santos said. "I kept us in the game and got the W."

Chacon's ailing right knee has recovered enough that he should reclaim his spot in the rotation Sunday, Tracy said. But the manager offered special praise for Santos.

"Great job by Victor," Tracy said. "He had some command issues early in the game, but he settled down and turned the game over to what has been a very, very effective bullpen."

To say the least.

While the Pirates' starters have won four in a row for only the second time all season, the relievers have not been scored upon in 8 2/3 innings during this streak.

On this night, it would take Salomon Torres, John Grabow, Matt Capps and Mike Gonzalez, one for each of the final four innings. With the crowd of 16,279 on its feet, Gonzalez closed it out for his 21st save, and Milwaukee was left with a total of two hits and one walk against the bullpen.

	THE RACE How Freddy Sanchez stands in his bid to become the first Pirates player to win the National League batting title since Bill Madlock in 1983. LAST GAME Yesterday: 1 for 3 with a single and a sacrifice bunt vs. Brewers. LEADERS Freddy Sanchez .345 Miguel Cabrera, Marlins .340 Chipper Jones, Braves .339 NEXT GAME Today: 7:05 p.m. vs. Brewers. Pitcher: Doug Davis. Sanchez is 9 for 20 lifetime vs. Davis.

"You can't say enough about what these guys are doing now," Tracy said.

There seemingly are not sufficient words to describe Chris Duffy's dramatic reversal, either.

He had been 3 for 32 since his return to Pittsburgh, then reached base 10 of 14 times against St. Louis. And last night, with Jason Bay's run of consecutive games ending at 307 because of a strained hamstring, the lineup again fed off Duffy. He went 2 for 3, reached three of four times, stole a base and scored twice.

Tracy was asked if he was surprised.

"I'm very pleased to see it, I can tell you that," he replied. "Where Chris Duffy is in that lineup, he can be a terrific player for us. And right now, his getting on base is the reason we've been able to do so many good things behind him. We have made a ton of productive outs lately."

Duffy singled to open the Pirates' first, took second on a wild pitch, boldly took third on Jack Wilson's lineout to shallow right and came home when Freddy Sanchez bounced out against a drawn-back infield.

Jeromy Burnitz took a more direct route by leading off the second with his 16th home run, sending a Dave Bush fastball halfway up the right foul pole.

It was Duffy again in the third, reaching on an error by first baseman Prince Fielder, stealing second, moving to third on Sanchez's sacrifice and coming full circle on Xavier Nady's grounder.

"The key is what those guys are doing behind me," Duffy said. "It's nice that I'm getting on base, and it feels good. But you're seeing some really unselfish baseball."

Then, it was the direct route again. Jose Castillo hit his 14th home run with two outs in the sixth, driving a Bush fastball the opposite way and barely clearing the Clemente Wall to put the Pirates ahead, 4-2.

"I didn't think that was going to be a home run," Castillo said.

Just about the only downer for the Pirates was that Wilson exited midway through the sixth because of a bruised knuckle on his right hand, the result of being hit by a pitch in the third. X-rays detected no fracture, but internal bleeding caused swelling the size of a golf ball.

Wilson downplayed it and said he hopes to play tonight.

The Pirates are 16-13 since the All-Star break and have taken all five meetings with Milwaukee at PNC Park this season.