Cain made his major league debut Monday and allowed two runs and three hits over five innings in a 2-1 loss to Colorado. The 20-year-old right-hander walked four and struck out two in a 103-pitch outing.
“Every single part of it was a great moment for me,” Cain said. “Hopefully I can cherish it and save it for as long as possible.”
The second-youngest player in the majors behind Seattle’s 19-year-old Felix Hernandez, Cain is a 2002 first-round draft choice who has quickly made his way through the Giants’ system. He went 10-5 with a 4.39 ERA in 26 starts at Triple-A Fresno this season.
“He has electric stuff, the kind of stuff you don’t see very often,” Giants catcher Mike Matheny said.
San Francisco swept a three-game series at Bank One Ballpark from June 28-30. The Giants are in position to do it again after winning their fourth straight, 9-4 on Saturday.
Randy Winn homered twice and Moises Alou also connected as San Francisco used four-run outbursts in the third and seventh innings to take command. Winn is 5-for-9 with three runs scored in the series.
The Diamondbacks have dropped four straight to fall eight games behind first-place San Diego in the NL West.
Third baseman Troy Glaus left Saturday’s game because of pain in his left knee. He appeared to hurt himself in the third inning while running the bases and is listed as day to day.
Arizona veteran Russ Ortiz is still looking for his first career win against his former team when he takes the mound Sunday. Ortiz, who pitched for the Giants from 1998-2002, is 0-2 with a 9.00 ERA in five starts against San Francisco.
Ortiz ended a personal six-game losing streak by giving up three runs and seven hits over 5 2-3 innings at San Diego in a 7-5 win Monday. He had been 0-6 with a 9.15 ERA over his previous eight starts.