I found it strange because neither has been pitching that well of late, especially Vargas. For both of them to pitch good games on the same day was just amazin' to me. May it happen more often.
The two don't compare as well in their last 10 starts. In his last 10, Perez was 6-4, giving up 26 earned runs and 58 hits in 59.2 innings. His ERA was 3.92. Vargas didn't fare as well. In his last 10, Vargas, also a lefty, was 3-3. He gave up more earned runs (33) and more hits (63) in fewer innings (51.1). His ERA was 5.79 ERA.