The Twins avoided a sweep in the three-game series to finish their homestand at 2-4 and stop Toronto's three-game winning streak.
The 23-year-old Romero (1-0) allowed no runs, four hits and three walks while striking out five over 5 2/3 innings.
Blue Jays starter Marcus Stroman (0-4) allowed two runs, six hits, one walk and struck out five in seven innings, his longest outing of the season.
Rosario hit his fifth homer of the season on a first-pitch two-seam fastball with one out in the second inning.
Blue Jays manager John Gibbons was ejected in the top of the third by plate umpire Dan Bellino after Teoscar Hernandez struck out swinging on an appeal play and Aledmys Diaz, who had stopped running between first and second thinking it was ball four, was caught stealing. It was the first time this season that Gibbons had been ejected.
The Twins added a run in the bottom of the third to move ahead 2-0 on an RBI groundout to first by Max Kepler. The Twins had loaded the bases on a single by Gregorio Petit, a walk by Jason Castro and a single by Joe Mauer.
Romero allowed a two-out walk to Kevin Pillar -- who had two singles on the day to extend his hit streak to seven games -- in the sixth and was replaced by Trevor Hildenberger.
Minnesota reliever Zach Duke pitched around a single in the seventh, and Addison Reed also pitched around a single in the eighth inning.
Aaron Loup replaced Stroman in the eighth inning, allowing one-out singles to Kepler, Eduardo Escobar and Rosario to load the bases. Robbie Grossman hit a sacrifice fly to right to increase the lead to 3-0.
After a walk to Logan Morrison loaded the bases again, Carlos Ramirez replaced Loup and walked Petit to force in the second run of the inning.
Fernando Rodney pitched a perfect ninth for the Twins in a non-save situation.
--Field Level Media
Toronto | Minnesota | |
Marcus Stroman | Player | Fernando Romero |
Loss | W/L | Win |
7.0 | IP | 5.2 |
5 | Strikeouts | 5 |
6 | Hits | 4 |
2.57 | ERA | 0.00 |
Toronto | Minnesota | |
Kevin Pillar | Player | Eddie Rosario |
2 | Hits | 2 |
0 | RBI | 1 |
0 | HR | 1 |
2 | TB | 5 |
.667 | Avg | .500 |