The Storm (18-22, 12-12 Iowa Conference) lost game one 4-3 before winning the nightcap 1-0.
Jake Barr hit a solo home run in the sixth inning, which was all the support Ruehle (4-2) would need.
The senior right-hander had been battling an injury to his throwing arm, but looked no worse for the wear on Saturday. He went six innings, allowed only one hit, struck out three and walked two. Rodriguez closed out the seventh inning for his third save of the year.
Dubuque added runs in the fourth, fifth and sixth. Andrew Danna finished with two hits and two RBIs and Noah Mahlik went 3-for-3. Spencer Kuehn drove in the winning run with a single in the sixth.
Chris Dorff (5-7) struck out three and gave up three earned runs in the complete-game. Kyle Staats (2-2) picked up the win in relief.
With Friday's win, Simpson clinched a spot in next week's Iowa Conference Tournament, which will take place at Veteran's Memorial Stadium in Cedar Rapids on May 10-12.