Boston @ Washington preview

Last Meeting ( Jul 2, 2018 ) Boston 4, Washington 3

The Boston Red Sox used an unlikely source of run production to get the jump on the Washington Nationals and can clinch a series win when the teams continue a three-game interleague set Tuesday night in the nation's capital. Rick Porcello's three-run double - his first extra-base hit in 35 career at-bats - off Nationals ace Max Scherzer fueled a 4-3 win for the Red Sox in Monday's opener.

Porcello also tossed six solid innings and Mookie Betts smacked a solo homer for Boston, which improved to 5-1 against National League teams. Anthony Rendon, Daniel Murphy and Bryce Harper each went deep for Washington, but the hosts left 10 runners on base while losing their third straight - all by one run. The Nationals have dropped eight of 10 overall and are a loss away from falling back to .500 for the first time since they were 17-17. Left-hander Brian Johnson gets the start Tuesday for the Red Sox opposite Tanner Roark for Washington.

TV: 6:05 p.m. ET, MLB Network, NESN (Boston), MASN (Washington)

PITCHING MATCHUP: Red Sox LH Brian Johnson (1-2, 4.28 ERA) vs. Nationals RH Tanner Roark (3-9, 4.10)

Johnson is making his second straight start since knuckleballer Steven Wright went on the disabled list. He was sharp Thursday at home against the Los Angeles Angels, allowing one run and three hits over four innings in a 4-2 win. The 27-year-old, who will be facing the Nationals for the first time, is 3-1 with a 4.14 ERA in eight career starts.

Roark finished June with his best start of the month by allowing one earned run across six innings in a hard-luck loss at Philadelphia. It was the only time in six outings last month that the 31-year-old did not allow a home run. Roark, who is 1-7 over his last 11 appearances (10 starts), owns a 3.22 ERA in 22 career games (19 starts) in interleague play and will be making his first career start versus the Red Sox.

WALK-OFFS

1. Murphy's home run was his first regular-season blast since Sept. 23, 2017.

2. Harper has two homers, four runs scored and seven walks over his last four games.

3. Boston optioned RHP Justin Haley to Triple-A Pawtucket and selected the contract of RHP William Cuevas from Pawtucket.

PREDICTION: Nationals 5, Red Sox 4