O'Neill, 20, solidified his status as one of the top young power hitters in the Minor Leagues this past season, clubbing 32 home runs -- tied for the second-highest total in the Minors -- in 106 games for Class A Advanced Bakersfield. And there's a good chance he would have given the Astros' A.J. Reed (34 HR) a run for the title had he not missed time while playing for Canada in the 2015 Pan American Games.
"I had a goal coming into the season that I wanted to do some damage, and I feel like I've done that," said O'Neill after the game. "Now I just want to carry it into next season and see what happens."
In addition to the home runs, O'Neill accrued 21 doubles and two triples -- meaning that 55 of his 106 hits (51.9 percent) went for extra bases -- and he also stole 16 bases in 21 attempts. Overall, the British Columbia native batted .260/.316/.558 with 87 RBI during his time in the hitter-friendly California League.
O'Neill has swung that bat well in the Fall League despite being one its younger position players. After going 0-for-3 with a pair of strikeouts in his debut, the 5-foot-11, 210-pound outfielder homered in back-to-back games prior to his 2-for-4 performance on Thursday.
"I feel good at the plate," he said. "Obviously it took a couple days to get my eyes back in tune to the pitches coming in, but I feel like I've got my groove back now and I'm just going to go from there.
"I think it's just all about getting reps down here," he added. "I'm just doing my thing and not trying to look too much into it -- just keep playing my game."
Although he put on a power showcase during the regular season, O'Neill's aggressive, free-swinging approach resulted in 137 strikeouts (30.7 percent) and 29 walks (6.3 percent) in 476 plate appearances with Bakersfield -- close to his career averages of 30.3 and 7.3 percent, respectively.
O'Neill understands that certain areas of his game will require more work than others, but, right now, he's only concerned with taking advantage of his opportunity this fall to play with and against some of the best prospects in baseball.
"Most of these guys are a level higher than me, even some guys from the big leagues," said O'Neill, "but I'm going to be facing this pitching next year, and I really want to succeed against them and prove I belong here."
Orioles No. 25 prospect Adrian Marin had a productive game out of the leadoff spot for Peoria, going 3-for-5 with a triple and a run scored. After playing shortstop exclusively during the first four years of his professional career, the 21-year-old has logged two games at third base this fall and made first-career start at second base on Thursday. Teammate Mike Yastrzemski, Baltimore's No. 13 prospect, went 0-for-2 but plated two runs -- both on sacrifice flies -- in the contest.
For Mesa, Rays No. 24 prospect Jake Bauers paced the offense with a solo home run as part of a 1-for-2 performance. Like Marin, the 20-year-old is learning a new position this fall, moving to the outfield from first base for the first time in his young career. Meanwhile, Tampa Bay's No. 5 prospect Daniel Robertson (No. 79 overall) went 1-for-4 with a double and scored a run for the Solar Sox.
Braves No. 7 prospect Lucas Sims started for Peoria and allowed one earned run on four hits in three innings. The 21-year-old righty walked one and struck out one, throwing 30 of his 44 pitches for strikes in the outing. Padres No. 11 prospect Ryan Butler picked up the win in relief for the Javelinas, allowing one earned run in his lone inning of work.