Tossing a no-hitter is an impressive feat on its own. Throwing two in the same day is almost unfathomable, but that's exactly what the Rookie-level GCL Nationals did on Sunday.The GCL Nationals used four pitchers to throw two combined seven-inning no-hitters in a doubleheader sweep of the GCL Marlins.Joan Baez,

Tossing a no-hitter is an impressive feat on its own. Throwing two in the same day is almost unfathomable, but that's exactly what the Rookie-level GCL Nationals did on Sunday.

The GCL Nationals used four pitchers to throw two combined seven-inning no-hitters in a doubleheader sweep of the GCL Marlins.

Joan Baez, the Nationals' No. 21 prospect, got things underway with six strong innings in the first game, which the Nationals won, 4-0. Baez, who hasn't yielded a run in three of his past four starts, struck out seven and retired the last 14 batters he faced before giving the ball to Jose Jimenez who pitched the final frame.

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Baez's 70-grade fastball and 60-grade curveball are among the best in the Nationals' system, but the 22-year-old has struggled due to the lack of a third pitch and inconsistent mechanics. Command has also been an issue for Baez, who issued 37 walks in 42 1/3 innings with Class A Advanced Potomac to begin this season.

Baez struggled with Potomac, going 1-6 with a 5.10 ERA in 10 starts, but was then placed on the disabled list and missed a month. Once healthy, Baez was sent to the GCL, where he has thrown well, posting scoreless outings in three of his four starts.

Jaren Johnson, the Nationals' 17th-round pick from last month's Draft, took the ball in Game 2. Johnson was making just his second professional start (seventh appearance) and threw four innings, the longest appearance of his young career.

That Nationals scratched across their lone run in the bottom of the fourth, setting the stage for 19-year-old lefty Gilberto Chu to finish off the historic day.

Chu did exactly that as he pitched the final three frames and ended the game emphatically with a pair of strikeouts.

William Boor is a reporter for MLBPipeline.com. Follow him on Twitter at @wboor.