Tyler Mahle's chances of throwing his second straight perfect game came undone just two batters into his start on Thursday. The Reds' No. 10 prospect still was plenty good, tossing six dominant frames to extend his scoreless innings streak to 19 2/3 for Double-A Pensacola.
Mahle needed just 88 pitches in his previous start to record the first nine-inning perfect game in the Southern League since 1970. He threw 94 (64 strikes) on Thursday, allowing four hits and one walk with seven strikeouts before departing with a 3-0 lead. The Blue Wahoos' bullpen would give back those runs in the subsequent frames, however, ultimately falling to Biloxi, 4-3, and costing Mahle an opportunity at his fifth win in as many starts.
The last time Mahle permitted a run was with one out in the first inning of his April 17 start against Jacksonville. The 22-year-old righty has since allowed just five hits during his scoreless streak, with 21 strikeouts and one walk.
Overall, Mahle is 4-0 with a 0.55 ERA and a .104 batting average against in five starts.
The rest of the best performances from top prospects Thursday
• No. 24 overall prospect Nick Senzel (Reds' No. 1) scored two runs and recorded multiple hits for a second straight game, going 3-for-6 with a stolen base in Class A Advanced Daytona's win over Jupiter. The 2016 first-rounder has seven hits over his past four games, during which he's lifted his average to .271. On the mound, right-hander Vladimir Gutierrez (Reds' No. 12) tossed five scoreless innings, allowing three hits with seven strikeouts, en route to his first Minor League win.
• No. 25 overall prospect Ian Happ (Cubs' No. 2) belted a grand slam and plated five of Triple-A Iowa's nine runs in a win over Colorado Springs. He finished 1-for-2 at the plate, also reaching twice via a walk, and now ranks second in the Minors with eight home runs.

MILB Video - Title: Happ belts grand slam - Url: http://www.milb.com/r/video?content_id=1330640883

• After two shaky starts to begin his season, No. 44 overall prospect Yadier Alvarez (Dodgers' No. 2) struck out seven batters in four scoreless innings for Class A Rancho Cucamonga. The hard-throwing righty yielded two hits and one walk in the outing before departing after 57 pitches (41 strikes).
• Braves No. 13 prospect Joey Wentz lowered his ERA to 2.70 as he scattered three hits and struck out seven over a career-high six scoreless innings in a no-decision for Class A Rome. The 6-foot-5 left-hander has given up two earned runs over his past three starts after allowing four earned runs on nine hits in his season debut.
• Blue Jays No. 12 prospect Max Pentecost extended his hitting streak to 12 games with a solo shot in the first inning before finishing 2-for-4 with three RBIs in Class A Advanced Dunedin's win over Charlotte. He's hitting .315/.345/.630 with five home runs and 14 RBIs through 13 games, two of which he's started behind the plate for the first time since 2014.
• Nationals No. 3 prospect Juan Soto connected on his third homer in a 2-for-4 performance for Class A Hagerstown. The second-youngest regular in the South Atlantic League, the 18-year-old Soto is batting .378/.452/.554 with twice as many walks (10) as strikeouts (5) through 20 games.

MILB Video - Title: Soto's solo shot - Url: http://www.milb.com/r/video?content_id=1329745483

• Phillies No. 13 prospect Rhys Hoskins homered in his second straight game, going 2-for-5 with a double and two runs scored for Triple-A Lehigh Valley. The 24-year-old first baseman extended his hitting streak to eight games in the process, during which he's improved his average from .297 to .348, and he's now gone deep six times in 20 games.

MILB Video - Title: Hoskins homers to left-center - Url: http://www.milb.com/r/video?content_id=1330403483

• Tigers No. 22 prospect Zac Shepherd powered Class A Advanced Lakeland past St. Lucie with a pair of home runs, hitting a solo shot in the third inning and then a three-run homer in the fourth. All five of the 21-year-old third baseman's homers have come during his current six-game hitting streak, during which he's batting .478 (11-for-23) with 13 RBIs and 10 runs scored.
• White Sox No. 18 prospect Bernardo Flores worked a career-high eight innings, allowed one earned run on two hits, to notch his third straight win for Class A Kannapolis. A seventh-round pick in 2016 out of USC, the 21-year-old southpaw threw 58 of his 87 pitches for strikes as he punched out six and generated another 12 outs on the ground.