VIERA, Fla. -- Bryce Harper and Ryan Zimmerman hit back-to-back solo home runs in the fifth inning Saturday, and Zimmerman upped his spring batting average to .500 with a 3-for-3 afternoon in the Nationals' 8-7 win over the Marlins.

Christian Yelich and Joe Mahoney each had two RBIs for Miami's split-squad, as Alex Sanabia -- battling for a spot in Miami's rotation -- gave up four runs in 2 2/3 innings.

Nationals starter Chris Young, a non-roster invitee, made his first start of the Grapefruit League season, and surrendered three runs on three hits and three walks in three frames. The big right-hander threw 52 pitches, 26 for strikes, while striking out two.

"Erratic," Young described his outing. "Just a little out of sync, but physically I felt fine. Shoulder felt really good. Felt good, everything physically. Just mechanics are a work in progress. I'd throw three good pitches and then four bad ones. It's not the consistency I'd like, but that's what Spring Training's for."

The Nationals scored first in the bottom of the second when Sanabia surrendered a leadoff single to Zimmerman -- who's rebounding from offseason shoulder surgery -- then walked Danny Espinosa and hit Kurt Suzuki with two outs. No. 9 hitter Steve Lombardozzi made Sanabia pay with a two-out, two-run single to right.

But the Marlins bounced back against Young with three runs in the third, including a Mahoney two-run homer to right field, his third of the spring.

The Nats tacked on two more in the third, before Sanabia left with a line of four runs on five hits and two walks, with two strikeouts, in 2 2/3 innings.

After Washington took the 4-3 lead in the third, Nationals reliever Craig Stammen ran into trouble to start the fourth. He gave up four straight singles to the bottom of the order, and the Marlins jumped out to a 6-4 lead. The Nats' homer surge off Brad Hand -- Zimmerman's first of the spring, and Harper's second -- tied it in the fifth.

Jose Fernandez, the Marlins' top prospect, pitched a quick sixth inning in his Grapefruit League debut and allowed just one hit in a scoreless seventh. The right-hander retired the side on 11 pitches in the sixth, recording one strikeout.

Up next: After two straight home games, the Nats will make their first trip of the spring to Lakeland, Fla., on Sunday to take on the defending American League champion Tigers. Harper, Wilson Ramos, Lombardozzi, Micah Owings, Ryan Mattheus and Drew Storen are expected to make the trip, along with starter Dan Haren. The 1:05 p.m. ET game will be broadcast live on Gameday Audio and WHFS 1580 AM in Washington.