Mehlich also named all-region.
Seattle claimed penalty kick shootout 4-2 after a double-overtime tie.
UNLV is looking for a third trip to the WAC championship game in four years.
Sophomore goalkeeper is the fourth from UNLV to earn all-district academic honors in the past four years.
UNLV will play in its fourth straight semifinal.
Senior forward is just one of three players to twice be named WAC Player of the Year.
UNLV is 6-3 on its home field this season, 4-1 against conference opponents.
Senior forward is tied for first in the nation.
UNLV will meet GCU in a rematch in the first round of the WAC Tournament on Wednesday night.
UNLV comes into the regular season finale tied with Seattle for second in the WAC.