The Rays' No. 2 prospect walked five, but allowed only one hit in four innings and relievers Brandon Henderson and Ryan Garton combined for five perfect frames to lead short-season Hudson Valley to a 2-0 win over Brooklyn and send the Renegades to the New-York Penn League Championship Series.
Guerrieri escaped an early jam in the first inning, walking the bases loaded before getting Stefan Sabol to fly out to end the threat. The lack of control was uncharacteristic for the right-hander, who walked five total in the regular season.
"It was rough, for sure," MLB.com's No. 69 prospect said. "I definitely struggled a little bit finding the strike zone throughout the entire outing. I was fortunate enough for the hitters to get themselves out and we won, so that's all that matters."
Drafted 24th overall in the 2011 First-Year Player Draft, Guerrieri has been dominant in his first professional season. The 19-year-old held opponents scoreless in six of his 12 regular-season starts, allowing only seven runs in 52 innings. His 1.04 ERA would have led the league had he enough innings to qualify.
In his latest scoreless outing, he picked up his first postseason victory with the help of a stellar performance by the Hudson Valley bullpen.
Henderson was especially effective, matching his longest outing of the year while not allowing a baserunner and striking out a season-high six in 4 1/3 innings of relief. Garton shut the door in the ninth, retiring the only two batters he faced.
"It's unreal," Guerrieri said of his bullpen's performance. "They've been consistent all year; they've been putting the work in. They've been competing as well as anyone on the team has. Some teams when [the starter] comes out of the game will have kind of a question mark with the reliever, but here it's not at all. You know they're going to give you what they've got and we usually come out on top."
Another Tampa Bay first-rounder provided the game's only scoring as Richie Shaffer -- the 25th overall pick in the 2012 Draft -- tripled home a run and scored on a wild pitch in the opening frame.
The Renegades will take on a Tri-City team that finished just one game behind them for the league's best record. The ValleyCats led the circuit in batting average, on-base percentage, slugging percentage and home runs in the regular season, and Guerrieri said his team must match that type of offensive production in the Finals.
"It's a great atmosphere right now in the clubhouse, no doubt about that. But we're looking to win again and take a championship home," the league All-Star said. "Hopefully [our strategy] is just to hit the ball and score a lot of runs, because our pitching is going to take care of the rest."
In other New York-Penn League action:
Tri-City 16, Auburn 7
Jesse Wierzbicki, Tyler Heineman and Neiko Johnson each drove in three runs and Austin Elkins scored four times as the ValleyCats outlasted the Doubledays to advance to the New York-Penn League Championship Series.
Tony Renda had a game-high four hits and Wander Ramos totaled three hits and three RBIs for Auburn. Box score