The Washington Nationals look to maintain their mastery of the Houston Astros when the teams meet Wednesday in the second half of a quick two-game set in Houston. A run in the eighth and another in the ninth lifted the Nationals to a 4-3 win in the opener Tuesday, which gave them five straight wins in the all-time series. Dating back to 2011, the Nationals have taken nine of the last 10 meetings.Adam LaRoche was the hero on Tuesday, delivering the tying and go-ahead RBIs, which gives him seven in the last seven games. Washington has won four of its last six following a 4-8 stretch, while Houston failed for the third time this year to record a third straight win. The Astros are 3-10 in their last 13 home games.TV: 8:10 p.m. ET, MASN2 (Washington), CSN Houston Plus (Houston)PITCHING MATCHUP: Nationals RH Jordan Zimmermann (1-1, 4.05 ERA) vs. Astros LH Brett Oberholtzer (0-4, 4.61)Since a dismal start against Miami on April 9, Zimmermann has allowed six earned runs in 20 innings over the course of three outings. He has 18 strikeouts against four walks in that span and has gone 14 straight innings without allowing a home run after surrendering three in the first 12 2/3 frames this season. Zimmermann is 1-2 with a 4.67 ERA in three career starts at Houston.After giving up one run in consecutive starts, Oberholtzer was reached for a career-high six in just 3 2/3 innings of a 10-1 loss to Oakland on Thursday. He surrendered eight hits for the second straight outing and gave up multiple home runs for the third time in 15 career starts. The 24-year-old, who has never faced Washington, has lost eight straight decisions.WALK-OFFS1. Washington is 12-1 when scoring four runs or more.2. Astros CF Dexter Fowler is 12-for-40 with seven walks during a nine-game hitting streak.3. Nationals RF Jayson Werth has hit safely in seven straight, while recording multiple hits in four of those games.PREDICTION: Nationals 5, Astros 3