The veteran manager was pleasantly surprised.
"The type of team that I have this year, guys have been getting opportunities to play a little more than I have in the past," Washington said. "So I think they're more prepared and more ready to go up there when there's opportunity for them to play and do the job."
He was particularly impressed with Garcia, who had three hits and scored four runs -- both career highs -- to become the first Texas rookie to record both since Jarrod Saltalamacchia in 2007.
"Leury Garcia was the one guy today that I didn't expect to make a whole lot of contact because he's the one guy that's in that lineup who hasn't been doing a whole lot of playing," Washington said. "He had a good game: scored four runs, got three hits, stole a bag, played good defense. That's what you like to have in extra guys."
Garcia was excited to contribute.
"It was awesome," he said. "I feel really good. I had a few days that I hadn't played but I was waiting for my time and I took advantage of it."
The Rangers set a season high for runs, and did it quickly. Martin led off the fifth with a home run and Beltre connected later in the inning for a 12-1 lead.
Beltre doubled twice and drove in four runs. He homered for the second straight day, hitting a drive that was originally called a double and changed to a homer after the umpires went to video review. Beltre connected off Edgar Gonzalez, signed by the Astros earlier in the day.
Beltre has heated up lately with 12 of his 23 RBIs coming in the last 10 games. He's raised his average from .214 to .260 in that span.
"Outstanding. Certainly what we needed," Washington said of Beltre's day. "He's been swinging the bat well and that average is climbing and RBIs are starting to pile up. He's my RBI guy, so I'm very happy."
At 10-28, the Astros are off to their worst 38-game start, according to STATS, breaking their 12-26 mark from 1967 and 1975.
Murphy's two-run homer came in a four-run third. Beltre hit an RBI double as the Rangers added three in the fourth, and Texas broke it open in the fifth.
Nick Tepesch (3-3) rebounded from two rough starts to allow four hits and one run in six innings, striking out a career-high eight.
The Rangers jumped on starter Jordan Lyles (1-1) for 11 hits and a career-high eight runs in four innings. He also balked home a run.
"I wasn't throwing the ball over the plate," he said. "I was missing by a little bit and missing by a lot, they hit me around pretty good, then I walked some guys, and they hit me around some more. The loss is definitely on my shoulders, and I've got to do a better job of competing."
Lyles was replaced by Gonzalez and he didn't fare much better, allowing six hits and four runs in four innings.
Lance Berkman extended his hitting streak at Minute Maid Park to 18 games with an RBI double in the first inning to make it 1-0.
Garcia singled to start the third, stole second base and advanced to third on an error by catcher Castro. Garcia scored on a groundout by Berkman.
Beltre doubled and scored on a one-out single by Craig Gentry in the third. Murphy then launched a 91 mph fastball into the seats in right field to extend the lead to 5-0.
Tepesch had allowed 11 runs and 14 hits in his last two games -- both losses -- but he was in control from the beginning on Sunday.
Carlos Pena singled with one out in the first inning, and the Astros didn't get another hit until Castro's homer with two outs in the fourth inning made it 8-1.
Martin opened the fifth with a towering homer to right field before back-to-back singles by Andrus and Garcia. Beltre connected on his homer and feel to his knee at the end of the swing before hustling to his feet. It was initially ruled a double, but a video review showed the ball hit on the center field wall above the yellow line and it was changed.
Castro had an RBI single in the eighth before Carter hit his team-leading ninth homer to the Crawford Boxes in left field off Derek Lowe to cut the lead to 12-5.
Barnes got Houston within 12-7 with a two-run homer in the ninth.
Bud Norris pitches for Houston when the Astros open a three-game series at Detroit against Anibal Sanchez on Monday. ... The Rangers travel to Oakland where Texas RHP Justin Grimm opposes A.J. Griffin. ... Houston designated RHP Philip Humber for assignment on Sunday and signed Gonzalez. ... Texas LHP Martin Perez was activated from the 15-day disabled list and optioned to Double-A Frisco. He had been on the disabled list since March 31, retroactive to March 22, after breaking his left wrist. ... The Astros struck out 12 times, giving them a big league-leading total of 381.