The Cubs' No. 4 prospect (No. 71 overall) responded to the challenge with one of his better performances of the season, while center fielder Pin-Chieh Chen came through with a walk-off, bases-loaded single with two outs in the bottom of the ninth inning to win the game, 3-2, and the series for the Pelicans.
Underwood Jr. allowed one run on five hits and struck out a season-high seven batters over six innings, throwing 54 of his 85 pitches for strikes. The 2012 second-rounder yielded a run in the third inning but bounced back to strike out the next five hitters and retire 10 of the final 12 batters he faced in the outing.
The 21-year-old right-hander missed 55 games during the heart of the regular season after he was placed on the 7-day disabled list on June 28 with an elbow injury. At the time, Underwood Jr. ranked fourth in the Carolina League with a 2.66 ERA through 64 1/3 innings.
The Cubs proceeded cautiously with Underwood Jr. following his injury, having him build up arm strength in the Rookie-level Arizona League before assigning him back to Myrtle Beach. The 6-foot-2, 215-pounder made just two starts for the Pelicans after his return to the mound -- during which he combined to allow two earned runs on six hits in nine innings - before toeing the slab on Wednesday night. He went 6-3 record in 12 starts during the regular season, finishing with a 2.41 ERA, 1.01 WHIP, 24 walks (2.8 BB/9) and 54 strikeouts (6.2 K/9) in 78 1/3 innings.
The Pelicans' offense provided Underwood with an early lead, pushing across one run in each of the first two innings. No. 22 prospect Victor Caratini started the scoring with a sacrifice fly in the first inning and finished the game 2-for-3 with a double. The 22-year-old catcher was 7-for-11 with three doubles and four RBIs in the three-game series.
Shortstop Gleyber Torres crossed the plate in the second, coming around to score on a Daniel Lockhart double after walking and stealing second base. The Cubs' No. 1 prospect (No. 31 overall) also laid down a sacrifice bunt in the ninth inning to put No. 9 prospect Mark Zagunis, who would eventually score the winning run, on third base.
Royals No. 15 prospect Alec Mills was strong in a no-decision for Wilmington, allowing two earned runs on five hits in six innings. The 23-year-old right-hander issued a pair of walks and fanned six before departing the game after 86 pitches (55 strikes). Mills posted a 3.02 ERA with 111 strikeouts and just 14 walks in 113 1/3 innings (21 starts) during the regular season.
Mike Rosenbaum is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.