The ability of Astros relievers to close out games, however, is a growing problem for manager Bo Porter, who watched his team lose for the fourth time this season when tied after eight innings when the Nationals rallied for a 4-3 win at Minute Maid Park.
"It's very concerning, because our starting rotation has done a really good job, and tonight you felt like you were in position to win the game," Porter said. "You had the right guys matched up, and we just didn't get it done. Their bullpen came in and closed it out."
The Nationals tied the game in the eighth inning against reliever Anthony Bass, and pushed across the deciding run in the ninth against Josh Fields (0-3), who has three losses with eight hits and nine earned runs allowed in 1 1/3 innings in his last three outings.
As a group, Astros relievers have a 6.04 ERA through 27 games.
"We're just going to continue to give them opportunities," Porter said. "We understand their strengths, and we're going to put them in position to be successful, and tonight it didn't happen."
Veteran lefty Raul Valdes was credited with a blown save after allowing Adam LaRoche's game-tying double in the eighth inning, which scored Jayson Werth, who began the inning with a single against Bass. Chad Qualls pitched out of a bases-loaded mess to keep the game tied.
Fields walked Denard Span to start the ninth, and Span was at third base with one out. Werth drew a walk on a tight 3-2 pitch, and LaRoche shot a single into right-center to score Span and put the Nats ahead, 4-3. Fields walked two batters in the inning.
"I felt just a little uncomfortable out there," Fields said. "[Catcher Jason] Castro, right before the last hitter, came out there and told me what he was seeing, and I threw strikes after that and was able to get out of the inning. I thought it was a little mechanical. I couldn't quite find my rhythm out there."
Nats closer Rafael Soriano pitched around a couple of two-out walks in the ninth, getting Jose Altuve (0-for-5) to fly out for the final out of the game. The win was the Nats' eighth comeback victory of the season.
"They had a good approach against a really tough pitcher, and lucky for us, we were able to come across with one in the ninth," Washington manager Matt Williams said. "The [bats] stung the ball all night."
For the second start in a row, Cosart left the game in line for a win and wound up without a decision. He allowed two runs and five hits and struck out six batters in six innings. Nats starter Gio Gonzalez had a similar line, giving up three runs and five hits while striking out nine batters in six innings.
Cosart put the Astros in a 2-0 hole by giving up a solo homer to Werth in the first and an RBI double to Jose Lobaton in the third, but Houston rallied for three in the third to give him a 3-2 lead. The big blow was a two-run, two-out single by rookie George Springer.
"That was a big hit," Porter said. "When you look at the momentum in which we had moving on the rest of the game, I felt pretty good."
Cosart finished with three scoreless innings to keep the lead, getting a big out to end the sixth, when he struck out Kevin Frandsen to strand a pair of runners he had walked. Since giving up seven runs in one-third of an inning April 18 at Oakland, Cosart has allowed four earned runs and nine hits in 12 2/3 innings.
"I've just been preaching efficiency with [pitching coach Brent] Strom, and trying to throw a lot more strikes and get ahead, and my walks didn't come until later in the game, so I was happy about that," Cosart said. "I just felt pretty consistent with everything from the very beginning. It's a good lineup over there, and obviously Werth is seeing the ball really well right now."
As far as the bullpen struggles go, Cosart maintains he has confidence in the relief corps.
"A starter's job is to go six-plus innings and keep us in the game as long as we can," he said. "I was able to do that after a bumpy start. It just didn't work out in the end."