Making a spot start for the injured Gaby Hernandez, Jesus Delgado was staked to an early lead, but it quickly became clear he would be in trouble in his first start with the Rainiers.
Oeltjen led off the bottom of the first inning with his third home run of the series, cutting the deficit in half, 2-1.
Delgado could not find the strike zone and handed out three straight base on balls to load them up with no outs in the first.
The Aces could not have asked for a better player to come to the plate with the bases juiced. John Hester’s liner to right field plated two runs and Reno (41-38) never trailed again. Hester is 4-for-4 on the year with the bases loaded and 13 of his 30 RBIs have come in that situation.
Tacoma (36-42) was able to tie it in the top of the second on a Jerry Owens sacrifice fly, but that was as close as the Rainiers would get in the series finale.
Oeltjen made it a 4-3 game in the bottom half of the second when he drew a walk, stole second and scored on Rusty Ryal’s team-leading 47th RBI. Ryal was a home run away from hitting for the cycle on the day.
Delgado, who only threw 25 of 63 pitches for strikes, got in trouble in the third and couldn’t get out of it. A walk, base hit and walk saturated the sacks for Oeltjen, who blew the game open with a grand slam – his fourth homer in as many games.
Reno built on its 8-3 lead in the fourth when Ryal led off with a double and came home on a double play, pushing the gap to 9-3.
Aces starter Yusmeiro Petit pitched three innings in a rehab stint for the Diamondbacks and gave way to Billy Spottiswood. Spottiswood picked up his first pitching win of the year and looked strong, retiring the side in order in the fourth and fifth innings.
He hit a little speed bump in the sixth when Chris Shelton and Bryan LaHair launched back-to-back solo shots to start the inning, but got out still leading 9-5.
Reno answered right back in the bottom of the sixth with a trio of runs thanks to a two-run shot by Josh Whitesell. Hester later scored on a double play for a 12-5 score.
The Rainiers added a single tally in the eighth when Owens drove in LaHair with a single.
The 5,720 in attendance thought the Aces might not be able to pull off the sweep after one half inning saw the visitors jump out to a 2-0 edge following a two-run double by LaHair. But Reno did not panic and was on its way to improving to 10-2 against Tacoma this season.
Tacoma out-hit the hosts 12-9, but it was poor pitching that did in the Rainiers. Tacoma walked 11 Reno batters, while four Aces pitchers did not issue a free pass.
Reno opens up a three-game series in Las Vegas today. First pitch is slated for 7:05 p.m.