Rangers prospect Miguel De Los Santos did not finish the Arizona Fall League season the way he started it, and that's precisely because he was starting -- but also because he was dominating.

The Texas farmhand struck out five over five one-hit innings -- and became the Fall League's lone five-game winner -- in the Surprise Saguaros' 12-2 victory over the Salt River Rafters on Thursday afternoon. The final game of both teams' regular seasons was predetermined to span seven innings.

The West Division champ Saguaros (26-10) would achieve the highest winning percentage in league history -- Mesa set the record at .705 with their 31-13 mark in 1999 -- by besting the East Division champ Rafters (22-16) a second time in Saturday's title game.

De Los Santos (5-0) retired the first 10 batters he faced before walking two unrelated Rafters in the fourth inning: Tim Wheeler (Rockies) on four pitches and Ryan Wheeler (D-backs) on nine. His no-no bid ended when the first batter of the fifth, Rob Brantly (Tigers), singled into right field on a 1-1 pitch.

"Left-handed hitter, I threw him a fastball for a ball and a fastball for a strike, then I tried to throw him a fastball in. I hit my spot and he made an adjustment," said De Los Santos of the one batter who got a hit off of him.

Known for his changeup -- the best in the Rangers' system, according to Baseball America -- De Los Santos added that he employed a quality slider and curveball in throwing 39 of his 59 pitches for strikes.

The Saguaros' potential one-hitter and shutout were lost in one fell swoop in the sixth. Reliever J.J. Hoover (Braves) allowed a two-run homer to Tim Wheeler.

On Oct. 29 in Phoenix, De Los Santos fanned eight over five one-hit innings and teamed with his bullpen on a one-hit shutout.

After pitching out of the bullpen in his first three AFL outings, the 23-year-old Dominican's final six appearances were as a starter. De Los Santos walked seven batters and allowed four runs in those three relief appearances, which spanned 4 1/3 innings, but, after converting to the starting rotation, he finished the season with a 3.26 ERA overall and a hold on the league lead in strikeouts: 40 in 30 1/3 innings.

"I am very happy," said De Los Santos, who split this year in the Minors between Class A Advanced Myrtle Beach and Double-A Frisco. "I didn't start the way I wanted to, but I made adjustments and I got myself back."

Following a five-run fourth, the Saguaros held a 10-0 advantage through five innings. Each of the club's first seven runs were plated in two-out situations.

Eight of the nine batters in Surprise's lineup recorded a hit, and the first seven batters each registered an RBI. The group burned through seven Salt River pitchers.

"Those guys, they don't surprise me," De Los Santos said of his supporting cast of swingers. "I can tell you, that's normal."

Royals' No. 4 prospect Christian Colon, the fourth overall Draftee in 2010, led the way with his 3-for-5, two-RBI effort.