Oswalt (4-0, 2.48 ERA), also in the midst of the best opening to a season of his six-year career, is 15-0 with a 2.41 ERA in 19 starts against the Reds, giving him the major league record for most wins against an opponent without a loss.
The right-hander is 8-0 with a 2.47 ERA in nine starts at Cincinnati. He went 4-0 with a 2.03 ERA in four starts against the Reds last year.