WHITEWATER, Wis. -- Sophomore pitcher Kevin Johnstone allowed just two earned runs in eight innings and senior first baseman Brett Ossola went 3-for-4 with a homer to lead fourth-seeded Case Western Reserve to a 7-3 upset of top-seeded St. Thomas (Minn.) on Friday in NCAA Midwest Regional action at James B. Miller Stadium.

Making his postseason debut, Johnstone (4-3) allowed three runs (two earned) on six hits and three walks with four strikeouts.

The Spartans played small ball early and got on the board in the bottom of the second with three runs on three hits and an error. Senior second baseman Paul Pakan and Ossola led off with back-to-back singles. An error on a grounder hit by junior designated hitter Andrew Frey allowed Pakan to score and Ossola to reach second. Sophomore catcher Robert Winemiller followed with a bunt single to set up back-to-back RBI ground outs by sophomore left fielder Kerrigan Cain and junior right fielder Jordan Dague.

In the top of the next inning, Johnstone's defense briefly let him down with back-to-back errors that followed a leadoff single and loaded the bases with no outs. Johnstone induced a ground-ball double play that scored a run and a grounder to the hole, which was gobbled up and gunned across the infield for the third out by senior shortstop Matt Keen.

The Spartans looked to get the run back in the bottom of the third as Keen was hit a by a pitch and moved to third with heads-up baserunning on a ground out. However, after Pakan was walked, a grounder by Ossola resulted in a double play due to runner interference.

After Johnstone retired the Tommies in order in the fourth, the Spartans picked up another run in the bottom of the frame as Frey led off with a walk that was followed by a Winemiller walk, a Cain sacrifice bunt and Dague's second RBI groundout.

A scoreless fifth followed before St. Thomas picked up one in the sixth on a sacrifice fly by Dylan Thomas. Two more runners reached scoring position with two outs, but Johnstone worked out of trouble with a strikeout.

In the bottom of the inning, the Spartans answered with a patient approach at the plate that yielded a pair of runs. Ossola, Frey and Dague all singled to load the bases before sophomore center fielder William Meador drew a two-out walk to force home a run. Later in the inning, Keen drilled an RBI single up the middle to plate Frey and make the score 6-2. 

St. Thomas came back with a single run once more in the seventh on an RBI double by Ben Podobinski, but Ossola countered in the bottom of the frame with a solo homer to left.

The first two Tommie runners reached in the ninth, but sophomore closer Daniel Sondag came out of the bullpen and induced a double play and a ground out to preserve the win.

Zach Franz (3-1) was the losing pitcher for the Tommies with three runs (one earned) allowed in 2.1 innings.