Underwood, 23, retired the first four batters he faced before permitting his first baserunner via a hit-by-pitch in the second inning. He wouldn't allow a knock until the sixth, when Jacob Nottingham delivered a single to center field.
Despite losing his no-hit bid, Underwood rebounded to retire the next two hitters before putting a bow on his outing with a perfect seventh inning.
After an inconsistent first half in the Southern League, Underwood has settled in to go 6-1 with a 3.38 ERA and a 1.07 WHIP in 53 1/3 innings (eight starts, nine appearances) since the midseason mark. He's thrown the ball particularly well of late, too, recording a 1.33 ERA and a 23-to-3 strikeout-to-walk ratio in his last 27 innings (four starts).
The rest of the best performances from top prospects Friday
• No. 58 overall prospect Fernando Tatis Jr. (Padres' No. 4) went 2-for-3 with a two-run home run to help Class A Fort Wayne edge Bowling Green, 8-7. The 18-year-old shortstop is now up to 20 homers, matching the TinCaps' single-season franchise record, in his full season debut. The multihit performance, meanwhile, lifted his average to .270 through 110 games. He's also stolen 28 bases, making him the only Minor Leaguer this season with at least 20 homers and 28 steals.
• No. 88 overall prospect Estevan Florial (Yankees' No. 4) hit his first Florida State League home run, connecting on a solo shot in the first inning for Class A Advanced Tampa before finishing the game 1-for-3 with three RBIs. The 19-year-old center fielder is slashing .324/.422/.486 and has hit safely in all nine games since being promoted to Tampa.
• No. 100 overall prospect Austin Hays (Orioles' No. 2) delivered a go-ahead two-run homer that proved the difference as Double-A Bowie defeated Portland, 4-2, in a five-inning, rain-shortened game. Hays' home run, his 28th this season and 12th for the Baysox, was the highlight of a perfect 3-for-3 showing at the plate. On top of his impressive power numbers, the 22-year-old outfielder is slashing .335/.370/.619 in his first full season, with 61 extra-base hits and 81 RBIs in 105 games across two levels.
• Make it 11 straight starts allowing two or fewer earned runs for Braves No. 9 prospect Joey Wentz. The 19-year-old lefty was sharp once again as he worked 5 2/3 scoreless innings, allowing four hits, in a no-decision for Class A Rome. Matching his season-high with 102 pitches (61 strikes), Wentz issued three walks and struck out eight in the outing. He's leading the South Atlantic League with a 2.31 ERA and ranks second with 132 strikeouts.
• Brewers No. 22 prospect Josh Pennington established a pair of season highs as he struck out nine over five scoreless innings in a strong outing for Class A Wisconsin. The hard-throwing righty gave up three hits en route to facing two over the minimum and throwing 47 of his 66 pitches for strikes. He's yielded nine hits while striking out 20 batters in his past 12 2/3 frames (three starts).
• Cardinals No. 24 prospect Ryan Helsley fired six no-hit frames to lead Double-A Springfield in a shutout of Corpus Christi. Making just his third Texas League start, the 23-year-old righty compiled six strikeouts against five walks while throwing 55 of his 91 pitches for strikes. A fifth-round Draft pick in 2015, Helsley was promoted to Springfield after he went 8-2 with a 2.69 ERA with 91 strikeouts and a .213 opponents' average over 93 2/3 frames (17 appearances) in the Florida State League. Using three pitchers, Springfield carried the no-hit bid into the ninth inning before surrendering a one-out double.
• Indians No. 14 prospect Conner Capel turned in his third straight multihit performance for Class A Lake County, going 3-for-4 with a home run, a double and four RBIs in a victory over Lansing. The 20-year-old outfielder has shown impressive tools in his full-season debut, producing a .783 OPS with 19 homers and 12 steals over 100 games in the Midwest League.
• Starting opposite Wentz, Red Sox No. 17 prospect Darwinzon Hernandez tossed a gem of his own, allowing two hits over a career-high 6 1/3 scoreless frames for Class A Greenville. The 20-year-old southpaw matched his season high with eight strikeouts while walking a pair and generating another six outs via ground balls. He's piled up 93 strikeouts in 83 1/3 innings (19 starts) for the Drive, all while posting a 3.89 ERA and a .218 batting average against.
• Yankees No. 25 prospect Billy McKinney stayed hot as he blasted his sixth home run in 13 games for Triple-A Scranton/Wilkes-Barre. The left-handed-hitting outfielder has hit 10 homers while slashing .331/.366/.669 in 35 games since moving up to the International League, making him a candidate for a possible callup in September.