JUPITER, Fla. -- Justin Maxwell delivered a three-run homer in the ninth inning to lift the Marlins to an unlikely 5-4 win over the Nationals on Friday at Roger Dean Stadium.
Maxwell, a non-roster invitee in the mix for a reserve outfield mix, homered in his second straight game.
"He's a good guy, who is interesting, he can play all three [outfield] spots," Miami manager Don Mattingly said. "He's got some experience. Great attitude guy. Great work guy. So far, obviously, he's swinging the bat good."
Michael Taylor and Wilmer Difo connected on home runs as the Nationals jumped out to a 4-2 lead. Difo delivered a three-run pinch-hit shot off Brian Ellington in the fifth inning.
Prior to the blast, Miami scored two runs in the fourth inning off Bronson Arroyo to claim a 2-1 advantage. Giancarlo Stanton doubled and Justin Bour had an RBI single. J.T. Realmuto delivered a run-scoring double in an inning the Marlins began freely substituting.
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Taylor's home run to right came in the second inning of Miami starter Adam Conley.
Gio Gonzalez, projected as either the Nationals' third or fourth starter, tossed two shutout innings. The left-hander retired the first five batters he faced, with one strikeout, before Realmuto's single to center. Cole Gillespie added a two-out hit, but Gonzalez escaped without allowing a run. Lucas Giolito, Washington's top prospect, pitched in with two scoreless innings, striking out three.
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Conley, competing for a rotation spot, looked sharp, pounding the strike zone in his two innings. Of his 17 pitches, 13 were strikes. The Nationals collected two hits off the left-hander, with one being Taylor's opposite-field home run with one out in the second inning.
Conley's velocity maxed at 94 mph.
In the third inning, Miami's Jarred Cosart struck out the side, but he was also shaken up on a freakish play. Brendan Ryan slapped a grounder down the first-base line. It appeared to be a double, but Stanton's throw to second was high, and third baseman Martin Prado was in short left field, backing up.
• Cosart escapes serious injury

With third base unoccupied Ryan sprinted to third as Prado and Cosart also were converging on the base. Prado rolled into Cosart, who tumbled over. He started limping but remained in the game.
After striking out Logan Shafer, Cosart left the game and had his right knee checked. It is believed to be nothing more than a bruise.
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Up next for the Marlins:Wei-Yin Chen, the Marlins' biggest offseason acquisition, makes his Grapefruit League debut on Saturday against the Cardinals at Roger Dean Stadium at 1:05 p.m. ET, airing live on MLB.TV and Gameday Audio. Marco Gonzalez is getting the nod for St. Louis. Chen is expected to be the No. 2 starter behind Jose Fernandez.
Up next for the Nationals: Stephen Strasburg will make his Grapefruit League debut against a familiar face when the Nationals face the Tigers on Saturday at 1:05 p.m. ET at Space Coast Stadium. Opposing Strasburg on the mound will be former teammate Jordan Zimmermann, who pitched in Washington for seven years before signing with the Detroit during the offseason. Left fielder Jayson Werth is also expected to make his first spring start. The game will air live on Gameday Audio.