SAN DIEGO -- San Francisco right-hander Jeff Samardzija will be filling the role of a stopper Saturday night when the Giants take on the Padres at Petco Park.

The Padres defeated the Giants -- and ace Madison Bumgarner -- 4-1 Friday night.

The one-game winning streak represents the totality of Padres successes against the Giants this season. San Francisco opened the season with nine straight wins against the Padres.

More from FoxSports

Not only did their domination of the Padres help the Giants post the best first-half record in the major leagues (57-33 at the All-Star break), it also tied the San Francisco Giants record for their best season-opening run against one team since the franchise moved west from New York for the 1958 season. The 1998 Giants opened the season by going 9-0 against the Marlins.

But now it is up to Samardzija (9-5, 3.91 earned run average) to prevent the Giants from losing a second straight game to the Padres, who are 19-18 since the start of June.

Samardzija has several things going for him, including the fact that his opponent is Rule 5 right-hander Luis Perdomo. The 23-year-old is 3-4 with a 7.48 ERA, although he allowed seven runs over 18 innings (a 3.11 ERA) in his last three starts of the first half.

Samardzija is 2-1 with a 1.57 ERA in three career starts at Petco Park. The Padres have hit only .177 against Samardzija at Petco Park.

"I like pitching in San Diego," Samardzija said recently. "I like the ballpark. It plays fair. If you make good pitches, you get outs."

Samardzija owns a career 6-1 record against the Padres with a 2.90 ERA in nine starts. He is 3-0 against the Padres this year with a 3.10 ERA in three starts covering 20 1/3 innings.

While the Giants are looking toward another even-numbered World Series title, the Padres are clearly in a rebuilding mode as evidenced by the Thursday trade that sent their most successful starter (Drew Pomeranz) to the Boston Red Sox for 18-year-old top prospect Anderson Espinosa.

The Padres have been stockpiling young pitching prospects through the draft, trades and international signings.

But they are also looking to Perdomo to develop into a front-line starter by the time the rebuild starts paying dividends around the 2019 season. Perdomo would be 26 at that time -- and could be the veteran of the rotation.

"I think we're going to see Luis in our rotation for some time," Padres manager Andy Green recently. "I like his stuff as well as his make-up. He doesn't rattle."

"Perdomo is making great strides," said Padres pitching coach Darren Balsley. "We knew this could be tough when we started giving him more responsibility due to injuries and trades that affected our rotation.

"But Luis has reacted far better than we could have expected. He's competitive. He wants to succeed. He's learning on the job. Last year at this time, he was in Single-A. This has been a huge step for Perdomo and he's not only accepted it, he's eager for more. He has confidence in himself and poise."