Nationals 4, Marlins 0 (1st): Doug Fister allowed only three hits to pitch his second career shutout as host Washington took the opener of a split doubleheader to clinch home-field advantage throughout the National League playoffs.

Fister (16-6) struck out nine, did not walk a batter and scored a run after recording a double as the Nationals won for the 11th time in 13 games. Anthony Rendon belted his 21st homer, Ryan Zimmerman and Asdrubal Cabrera each knocked in a run and Adam LaRoche added two hits for Washington.

Donovan Solano collected a triple and two singles for Miami, which has dropped six of its last eight contests. Jarred Cosart (13-11) issued a career-high eight walks while giving up three runs (two earned) and four hits over five innings.

Rendon belted a 2-1 pitch into the left-field seats with one out in the first inning and LaRoche followed with a single, moved to third on Ian Desmond’s double and scored on a passed ball for a 2-0 lead. Two walks and a fielder’s choice set the table in the fifth before Cabrera’s RBI infield hit made it 3-0.

Fister led off the sixth with a double and later trotted home on Zimmerman’s two-out single to center field to extend the lead. Miami did not put two runners on base in any inning against Fister, who recorded his other shutout Sept. 22, 2012 against Minnesota and has seven career complete games.

GAME NOTEBOOK: Washington CF Denard Span returned after missing the last two games with a sore right knee and notched his career-high 181st hit in the sixth inning. Span had 180 hits with Minnesota in 2009. … Solano has recorded multiple hits in four of his last nine contests. … The Nationals worked a season-high 10 walks, two more than the previous best June 11 against San Francisco.