Trentacosta slams door on Cowlitz in Knights' 2-1 win.

Closer Mark Trentacosta (pictured) recorded his ninth save of the summer, one short of the team record, and Corvallis put a serious crimp in Cowlitz's playoff hopes with a 2-1 victory.

Called on to protect the slim advantage starting the ninth, Trentacosta allowed a leadoff single and then slammed the door on a fielder's choice, a strikeout and a grounder to second to send Cowlitz (27-25) to the brink of postseason elimination.

The Black Bears must sweep the final two games of the series to join the Knights (40-16, 36-16 WCL) in the West Division playoffs. Otherwise the Knights will face Bend (29-25) in the best-of-3 series, which starts Friday night at the No. 2 seed's venue.

Trentacosta's nine saves are one short of Taylor Starr's franchise record, set in 2008. He has not allowed a run in 21 consecutive innings in his last 14 relief appearances; he has seven saves and three wins in that span.

Not bad for someone who did not pitch this past spring after transferring to UC Irvine from Golden West CC, where he was an Orange County Empire Conference all-star as a sophomore in 2010.

"It's been great," the 20-year-old lefty said, speaking of his summer with the Knights, where he�s 3-1, 1.47, with 34 strikeouts in 30.2 innings. "I just wanted to come out and pitch.

"It had been a year since I'd pitched in a game and I love being on the mound."

A 6-foot-3, 205-pounder from Orange, Calif., Trentacosta was 9-5, 3.39 in two years as a starter at Golden West College. He had four complete games, and pitched 175.1 innings.

He quickly altered his mentality this summer. He saved the Knights' home opener back on June 7 and has not relinquished the closer role. Five of the six runs he allowed, and his lone loss, came in his only start and he's 3-0, 0.27 in 18 relief appearances.

"It's a different change of pace," he said of relieving. "When you're a starter you have to lengthen yourself out, as opposed to closing, where you go all out at once. It�s an adrenalin rush."

The Knights have now won eight games in row, 14 of 15 and 24 of their last 28 since being swept by Bend on July 3-5.

Corvallis scored in the first on a leadoff walk to Trent Oleszczuk, a wild pitch and an RBI single by Kramer Scott. Cowlitz strung three singles off Jace Fry to tie in the sixth.

Oleszczuk was hit by a pitch to lead off the eighth, the team-high 10th time he's been plunked. He moved to third on a sacrifice by Scott and an infield single by David Armendariz, and scored the winning run on a wild pitch.

Fry allowed four hits in six innings, with four strikeouts. Reliever Jimmie Sherfy got his first win and continued his excellent late-season work by striking out four in two scoreless innings.

Sherfy has not allowed an earned run in his last 10 innings over six appearances, with 15 strikeouts.

The run allowed by Fry was the first by a Knights' starter since the first inning of a July 30 loss to Bend. Since then Nick Hoover (2), Fry (6), Chris Johnson (5), Kyle Hart (7) Chase Johnson (5), Max Beatty (5.1), Sebastian Santos (4), Mendoza (6) and Fry (5.2) had combined for 46 straight scoreless innings before Cowlitz broke through with two outs in the sixth.

Corvallis hosts Cowlitz at 7:15 p.m. Tuesday on Wilson Motors Night in its regular-season home finale. A fireworks show will follow. The teams conclude the regular season at Cowlitz on Wednesday.

The Knights will travel to either Bend or Cowlitz on Friday for Game 1 of the West Division playoffs. Games 2 and Game 3 (if necessary) will be at Goss Stadium on Saturday and Sunday, starting at 6:40 p.m.