It’s tough to win without your ace.

With Jace Stoffal mysteriously scratched on Friday, the situation turned from concerning, to hopeful, to straight-up mystifying in the series’ conclusion on Sunday. No. 17 Oregon fell meekly on Friday, bounced back in impressive fashion on Saturday, but barely showed up in Sunday’s rubber game against USC.

Also not showing up was Stoffal. There was speculation he could get the nod on Sunday, and D1Baseball’s Kendall Rogers even tweeted on Saturday morning that Stoffal was not injured and was expected to start this weekend.

That did not happen.

With just minutes until game time, the Ducks hadn’t released a lineup. They ended up going with Matthew Grabmann, leaving the Stoffal mystery unsolved. Grabmann had been effective in unextended action this year, and the freshman hoped to do his best Stoffal impression to help Oregon take the series.

That also did not happen.

Grabmann had his worst outing of the year, imploding in ugly fashion with two outs in the second inning. The Ducks were hardly ever in Sunday’s game. They fell 11-4 and dropped the series to USC.

Rikuu Nishida led off the game with a single, then stole his 19th base of the year. That broke Oregon’s single-season stolen base record, which was set by Don Banderas in 1965.

Drew Cowley worked yet another good plate appearance with a walk, but a couple flyouts left the Ducks empty-handed in the opening frame.

Grabmann had an okay first inning, issuing just a walk. In fact, he was fine for the first 1 2/3 innings. He gave up an infield hit to lead off the second, but was an out away from escaping unscathed.

The wheels fell off and skidded recklessly down the road with two outs. A single and a walk loaded the bases, and a hit by pitch drove in a run. Back-to-back hits brought in three more runs, and the second infield single of the inning put the finishing touches on the six-run beatdown.

The Ducks tried to chip away, but they left some important runners stranded. Sabin Ceballos grounded into a double play with runners on the corners and one out in the third. They finally got on the board with an Anson Aroz RBI double in the fourth — in Aroz’s first start at catcher — but they left two in scoring position.

Fellow Canadian freshman Turner Spoljaric replaced Grabmann after two innings. Spoljaric had an eerily similar outing as Grabmann. He was okay for 1 2/3 innings, but then imploded with two outs in the fourth. USC rallied for four more runs, extending Oregon’s deficit to 10-1.

Cowley, who’s on the hottest stretch of his career, sent another home run flying in the fifth inning. It was his seventh in the last nine games and 13th of the year, continuing a surprising power surge. Ceballos made it back-to-back with his second home run since returning to the lineup. The solo shots trimmed USC’s lead to 10-3.

Jackson Pace pitched a scoreless fifth, helping his own effort with a pickoff. Matt Dallas gave up a run in the sixth on Oregon’s third hit batter of the game and a run-scoring single.

Nishida and Colby Shade reached to start the seventh, but Shade got thrown out trying to advance on a wild pitch. USC made a throwing error on a pickoff attempt, allowing Nishida to score. Oregon stranded two more runners, unable once again to get any kind of real rally going.

The Ducks fell meekly into the afternoon and ended their series on a sour note. Grayson Grinsell pitched two scoreless innings, but the offense had no response.

No. 17 Oregon (31-15, 14-9 Pac-12) will look to get back on track in its final home series of the year this weekend against Washington (27-14, 12-10 Pac-12).