The young left-hander was nearly untouchable from then on, turning in his best performance of the season in a 5-4 win over the Angels at Rogers Centre. Rzepczynski got out of a jam in the top of the first, and the next time he left the dugout, he did so with a four-run lead, as the Jays teed off on Angels starter Sean O'Sullivan.
The win snapped a five-game losing streak for the Blue Jays (56-64), who had lost eight of their previous nine contests.
In only his ninth career start -- and first against the Halos -- Rzepczynski pitched a season-high 6 1/3 innings, limiting a potent Angels (73-57) lineup to just three hits and a walk while striking out six.
"Great job, outstanding," Blue Jays manager Cito Gaston said of the rookie's performance. "The first inning, he looked like he was a little nervous about who he was facing over there -- you're facing probably one of the top-hitting teams in baseball. I think maybe after that first inning, he kind of thought, 'Well, I can get these guys out, too,' and he did a great job. Outstanding."
The Blue Jays want to avoid risking injury to their young pitchers, and they plan on shutting down Rzepczynski and fellow rookie Brett Cecil soon, as they hit their innings limit for the season. With Friday's performance, Rzepczynski is making the most of his few remaining starts -- which could help serve as an audition for the club's rotation in 2010.
"He was as billed," Angels manager Mike Scioscia said of Rzepczynski. "You see a guy with good life on his fastball, good movement, who gets his slider under swings. He moved the ball around and threw a lot of strikes."
After walking center fielder Torii Hunter in the first inning ahead of the big Guerrero strikeout, Rzepczynski (2-3) allowed only one base hit and no walks over a span of 19 batters.
"Something about the first inning -- I don't know what was going on -- wasn't me," Rzepczynski said. "And then I sat down [in] the middle of the first ... and I was able to refocus and give the team a chance to win.
"The big thing with them is just getting ahead, and pitching your game and not letting the lineup dictate what you can do."
Rzepczynski, who lowered his ERA to 3.65, recorded a win for the first time since July 18, as the southpaw has been on the losing end of close decisions in which the offense came up just short. That wasn't the case Friday, as the Jays got out to a 4-0 lead in the first inning and widened the gap to 5-0 by the time Rzepczynski's night was over.
Gaston felt the early cushion -- a rarity for the Jays of late, as the club's offense has sputtered at times this season -- worked in Rzepczynski's favor.
"It always helps," Gaston said. "It would help anyone to get a lead early, get a little breathing room. You can make some mistakes and get away with it. That was real important that we got some runs, especially against that team over there. They can beat you a lot of different ways."
Second baseman Aaron Hill got the offense going with a one-out home run off O'Sullivan -- Hill's club-leading 29th blast of the season -- with one out in the first to open a 1-0 lead.
The Jays strung together three hits and two walks with two outs against O'Sullivan (3-2), who left after one inning plus one batter. A double by center fielder Vernon Wells plated one run, and a bases-loaded single by third baseman Jose Bautista scored another two to cap off a four-run first.
In the third, Wells belted the club's second home run of the night -- a towering shot to left field that landed in the second deck -- to give Toronto a 5-0 advantage.
The Jays were cruising until the ninth inning, when reliever Brandon League put two runners on base. But Hill came up with a potentially game-saving play in the next at-bat, when he made a leaping grab to snare a hard-hit line drive off the bat of Rivera.
The play loomed large in light of what happened next, as Casey Janssen -- who replaced League after the Rivera at-bat -- gave up a home run to Mike Napoli to narrow the Jays' lead to 5-4.
"The guy [Hill] made a great play," Napoli said. "Juan hit the ball hard. It might have been a little different if we had the bases loaded there when I came up. It didn't happen."
Despite the ninth-inning hiccup, Friday's win was the polar opposite of Thursday's rough loss, in which the Jays pitched poorly, struggled at the plate and committed three errors en route to an 8-1 thrashing by the Red Sox.
"The way we played our last series, we needed to play better baseball all around," Wells said. "Marc came out and did a great job and gave us some quality innings. Guys got hits when we needed them."
While what happens in Spring Training next year will help determine who makes Toronto's rotation in 2010, Rzepczynski is taking advantage of his time in the Majors to show that he can compete at the highest level.
But the lefty's top priority is still to help the team this season.
"However many starts I've got left, I'm just going out there and trying to do the best I can," Rzepczynski said. "Next year, it'll be nice to give an impression, but right now, I'm just going out there and trying to give the team a chance to win. That's the main thing."
Erika Gilbert is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.