"He just kept the ball down, did a good job, made his pitches," said Vancouver manager Gary Pearson. "We didn't do a good job making adjustments, so we helped him out a little bit."
Mateo fired a 7-hitter and totaled 4 strikeouts and no walks in the shutout performance.
So far this season Mateo has a 6-6 record with a 2.66 ERA.