Conant reliever Mason Sykes earned his biggest save of the season Wednesday — as a starter.

Sykes extended the Cougars’ season by pitching a complete-game 2-1 win over second-seeded St. Charles East in the Class 4A Bartlett baseball regional semifinals.

Conant — seeded 18th and having twice beaten two higher seeds — will face the winner of Thursday’s contest between Bartlett and Glenbard West for the regional title on Saturday.

“Mason did a great job. He’s been kind of a closer for us this year,” said Conant coach Derek Fivelson. “But we felt good about him starting this game.”

Sykes, aided by two late-inning double plays, allowed only 3 hits and walked two. The junior right-hander also a good day at the plate, going 3-for-3 and batting in a run.

“My command was really good. I was being very efficient. I was locating my pitches. Even ones (the umpire) was calling balls, I was painting the corners really well,” Sykes said. “My breaking ball wasn’t working but my fastball did the job.

Niko Klebosits pitched well for the Saints. Klebosits, who pitched into the sixth inning, struck out six.

“We pitched well enough. We played good enough defense. It was a solid day for us there,” said East coach Len Asquini. “We certainly struggled all year to produce runs and we saw it here again today.”

Conant (15-18), after threatening in the first and second innings, took the lead in the top of the third.

CJ Deshazer led off with a double to left, advanced to third on Logan Smith’s single up the middle and scored on a Sykes single.

Prior to Sykes’ at-bat, Deshazer survived a close play at third. While Smith got caught in a rundown between first and second, Deshazer broke for the plate. He dove back to third base and appeared to be tagged out by Saints third baseman Thomas Adams. The umpire called him safe after the ball popped out of Adams’ glove.

“The play at third base was a tough one,” Asquini said. “If the ball just stays in his mitt, it would have been a little different. They wouldn’t have scored a run off of that.”

Smith scored the second run on a Sam Ryan sacrifice fly.

East (21-11) got back one run in the fourth. Kyle Tiltges connected on a 2-out double to left and scored when John Carroll followed with a 2- bagger to right.

The Saints prevented another Conant run in the fifth. Tyler Hedman tried to score all the way from first on Sykes’ double but was thrown out at the plate on John DelloStritto’s throw from center field to Klebosits, who was covering the plate.

Strong plays by Ryan, Conant’s second baseman, help preserve the Cougars’ win. The junior assisted in 5 of the Saints’ last 6 outs. After fielding a grounder for the first out of the sixth inning, Ryan ended the frame by starting a 4-6-3 double play. He turned another in the seventh, when he speared Patrick Griffin’s line drive and then doubled up Carroll at second.