For five innings, Clayton Blackburn's outing and Matt Purke's were locked in a terrific pitchers' duel, but the sixth inning was one pitcher's undoing.
The former was spectacular early on, striking out 10 without allowing a hit through the first five innings before allowing four runs on six hits in the sixth frame. Purke, meanwhile, continued his string of zeros on the day, finishing with only two hits and two walks allowed in six innings, to help Double-A Harrisburg defeat Blackburn's Richmond squad, 5-0, in a Wednesday matinee.
Blackburn -- the Giants' No. 8 prospect, according to MLB.com -- would have been perfect going into the sixth had it not been a throwing error by shortstop Matt Duffy in the first inning. He struck out the side in the second and fourth frames and added two more K's in the fifth.
The 21-year-old right-hander tied a career high with the 10 punchouts. He hit double digits twice in 2012 with Class A Augusta, most recently on Aug. 20 of that season against Savannah.
Wednesday marked the first time this season Blackburn had allowed more than two earned runs in a start. The Richmond starter is 2-3 with a 2.78 ERA, 27 strikeouts and six walks in his first six Double-A starts (32 1/3 innings).
Purke, on the other hand, used his sixth outing to turn around his 2014 campaign. The 23-year-old left-hander and No. 6 Nationals prospect allowed fewer than three runs for the first time this season. After giving up four earned runs in three consecutive starts, he entered the day with an 0-5 record and 9.30 ERA but saw those stats improve to 1-5 and 7.18 following the gem.
The Senators southpaw has struggled with his command so far with a 17-to-15 strikeout-to-walk ratio through 26 1/3 innings this season. He walked only 25 batters in 90 innings last season after starting the season late while recovering from 2012 shoulder surgery.