The teams will meet again later Saturday, with the winner advancing to the championship game Sunday.
The Red Raiders (39-16) broke the game open with a four-run fifth inning that included a two-run homer by co-Big 12 Player of the Year Josh Jung.
Texas Tech starter Mason Montgomery lasted just 1 1/3 innings, but the Red Raiders' bullpen came through. Ryan Sublette gave up one run in 4 1/3 innings to get the win and Dane Haveman threw three shutout innings to earn the save.
Marques Inman and Ivan Gonzalez each had two hits for No. 4 seed West Virginia (36-19).
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