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While the San Diego Padres' James Shields has pitched much better than his record indicates, Jake Peavy of the San Francisco Giants is deserving of his poor mark.

Peavy is the only Giants pitcher to lose in the last two weeks but will try to help them stay hot Wednesday with a sweep over his former team.

That would be nothing new for San Francisco (29-19) as it has already swept two series against its NL West foe, including last week in San Diego to close a 7-0 road trip. Tuesday's 8-2 victory gave the Giants eight straight wins over San Diego (19-28) and 10 consecutive at AT&T Park.

It also was the Giants' 12th win in their last 13 games to push their division lead to 4 1/2 games over the Los Angeles Dodgers.

San Francisco has already beaten Shields twice this season, though not due to any shortcomings by the right-hander. He held the Giants to three hits and a run in seven innings of a 1-0 loss on April 26, and he fell victim to another low-scoring affair in Thursday's 3-1 defeat - his fifth loss from a quality start.

Shields (2-6, 3.07 ERA) held the Giants to three runs in 6 2/3 innings while walking one and striking out seven. His ERA moved to 3.40 in eight career starts against them, the last four San Diego losses.

Shields has tossed at least six innings in each of his nine starts, but the Padres are 2-7 in them. They have supplied him just 13 runs in those games, and his 1.99 run support average is the only one south of two runs in the majors among qualifying pitchers.

After Monday's 1-0 series-opening loss, San Diego manager Andy Green held a 10-minute closed-door meeting to address his team. A point of emphasis was scoring runs.

"We have, from a pitching perspective, for the most part put ourselves in a position to win baseball games," Green told MLB's official website. "I think there's more than enough in that clubhouse to go out and actually win those games more consistently than we are. So we've got to raise the bar."

Peavy holds a similar record to Shields at 1-5, though his 8.21 ERA is much more telling as to why. The 15-year veteran has allowed at least five runs in four of his starts already.

Peavy, who spent the first eight years of his career with the Padres, has lost four of his last five starts. He holds a 9.58 ERA in that stretch, which was capped by his shortest regular-season start since July 6, 2010.

The Chicago Cubs shelled Peavy for seven hits and five runs in 1 2/3 innings on Friday. He walked two and finished without a strikeout for the first time since August 2013.

All five runs came in a disastrous second inning. Somehow, Peavy still found a silver lining.

"I felt better tonight, stuff-wise and with life (on pitches)," Peavy told MLB's official website. "When teams are going that well and are that professional, you have to earn your wins and they're going to make you throw your 3-2 pitches."

The difference between the Cubs and Padres is huge. Chicago leads the NL with 5.61 runs per game, while San Diego ranks toward the bottom with 3.49.