PITTSBURGH -- The Padres came into and left Thursday's game with the same question on their minds: Who is Yoslan Herrera?

The Pirates rookie, who struggled through his first two Major League starts earlier in the month, threw a nearly flawless six innings against the Padres to lead Pittsburgh over San Diego, 9-1, at PNC Park.

Herrera came into the game with a 19.50 ERA after giving up 13 runs in six innings in his first two starts.

"He's in the Major Leagues for a reason," Padres manager Bud Black said. "Maybe those numbers aren't indicative of his talent."

Apparently not, because Herrera showed no signs of immaturity on Thursday. He used a variety of off-speed pitches to keep the Friars on their heels, striking out four and walking only one.

Herrera allowed only one runner to reach third, but got Brian Giles to ground out in the third inning to quickly extinguish the Padres' only serious threat early in the game.

"He threw his pitches for strikes," Nick Hundley said. "He attacked the zone. He threw both of his off-speed pitches for strikes. On film he looked like he got behind a lot before, but today he was ahead in the count and threw the ball well."

Padres starter Clay Hensley, who was making his first Major League start since Aug. 25, 2007, did not fair as well against one of the National League's most productive offenses.

The Pirates jumped out to a 2-0 lead in the first on catcher Ryan Doumit's RBI double and left fielder Jason Bay's sacrifice fly. The right-hander then surrendered two more runs in the fourth when Bay and Xavier Nady, both former Padres, hit back-to-back home runs to left field.

Two more runs were added to Hensley's total in the sixth after he allowed Nady and first baseman Adam LaRoche to reach base. Reliever Justin Hampson then walked in a run and center fielder Nate McLouth's sacrifice fly brought in LaRoche to make it 6-0.

Despite the sour stats, both Hensley and Black took positives out of Thursday's game. Black said Hensley made adjustments later in the game and was able to effectively move his fastball.

"I felt pretty good," Hensley said. "I just think a couple pitches got away from me. It hurt. I think the results were probably a little worse than I felt tonight.

"I felt like I could have executed some pitches better," he added, "but for the most part I think I felt all right."

The Padres got limited offense in the eighth when Adrian Gonzalez singled home Jody Gerut for San Diego's lone run.

The Pirates scored their seventh run in the eighth when Kevin Kouzmanoff couldn't come up with Luis Rivas's dribbler between short and third, scoring Doug Mientkiewicz. McLouth, the Pirates All-Star outfielder, followed Rivas' single with a deep blast to right field to make it 9-1.

The loss is the Padres' ninth in their past 10 games. It was the Friars' 65th loss of the year, which they didn't pick up until Sept. 9, last season.

Several local Padres supporters were in attendance at PNC Park. Outfielder Chase Headley had 27 family members and friends wearing T-shirts with his name and number in the left-field bleacher seats. Headley's aunt and uncle are from nearby Cranberry, Pa.

The game was also a homecoming for shortstop Khalil Greene, who hails from Butler, Pa., a suburb outside of Pittsburgh.