The Redbirds, who were coming off a 3-2 late-night Friday victory over the Huskies, fell to 6-5 while Washington improved to 7-6.
Redbird starter Brent Headrick (1-1) allowed all five runs, four of which were earned, and gave up eight hits while striking out a career-high eight.
Washington’s Jordan Jones (2-2) picked up the complete-game victory, allowing four hits and fanning 11. He gave up doubles to ISU's Collin Braithwaite and Nick Zouras. Braithwaite and Joe Aeilts drove in runs.
Game three of the four-game set begins at 3 p.m. on Sunday and will be broadcast via leanStream on GoHuskies.