"These are great wins," manager Bud Black said. "It makes you feel better about everything."
John Baker led off the ninth with a double. Mark Kotsay and Chase Headley singled with one out. Logan Forsythe reached on a fielding error by third baseman Chris Johnson, scoring Baker from third. Myers hit Carlos Quentin with a pitch with the bases loaded, tying the game.
"I sucked," Myers said. "I gave up runs. That's not my job. I'm supposed to shut down the inning and I didn't do it."
With two outs and a 2-1 count, Amarista became just the fifth Padres player to hit a grand slam for his first career home run. He said through a translator that he didn't think the ball would clear the fence. Moments after, Amarista had a huge smile on his face.
"I was just happy," Amarista said. "It was my first home run and my emotions got to me."
Amarista wasn't the only one with a memorable evening. Reliever Nick Vincent earned his first Major League victory despite giving up a run in the eighth.
"Yeah, it was not the way everybody wants it to be," said Vincent, who made his Major League debut on Tuesday. "A win's a win, so I'll take it."
The six-run rally saved the Padres from wasting a strong effort from their starting pitcher for the second night in a row.
Cashner, for most of the night, was dominant, striking out nine and walking just one in 6 1/3 innings. Born and raised 40 miles from Houston, Cashner had a sizable contingent of fans in right field.
After Carlos Lee singled to break up Cashner's no-no in the seventh inning, Brian Bogusevic homered after fouling off seven pitches, giving the Astros a 2-1 lead.
Cashner said he never thought about his bid for a no-hitter.
"I just try to make pitches," Cashner said. "After I gave up the hit to Lee, I was really just trying to lock in and get a double play right there. I wasn't able to do that."
Coming off three solid starts while getting stretched out at Double-A San Antonio, Cashner breezed through the first five innings. He retired 19 of the first 20 Astros batters, walking only Jason Castro in the second.
In the fifth inning, Castro hit a sharp line drive toward first baseman Yonder Alonso, who made a diving snag to his right to preserve Cashner's no-hit bid.
The right-hander struck out the side in the third and sixth innings. With 101 pitches, Cashner left the game after giving up the homer to Bogusevic on the 10th pitch of the at-bat.
Black said he didn't know what he would've done if Cashner had maintained the no-hitter through the seventh with a quickly rising pitch count. After all, the guy on the mound was a reliever on June 5.
"It would've been nice to have those decisions to make when you're talking about something significant like that," Cashner said.
Cashner's fastball hit 100 mph in the first inning, and he was able to keep it above 96 into the seventh.
"I felt like I had better stuff when I was in the Minors and tonight I felt like I still had my fastball there in the seventh," Cashner said. "I feel like my legs are really strong right now and I can hold my velocity."
The Padres were kept in check for eight innings by Astros starter Dallas Keuchel and relievers Rhiner Cruz, Brandon Lyon and Wesley Wright.
San Diego took a 1-0 lead in the third behind a two-out homer from Chase Headley that hit high up the wall over the left-field fence. In the sixth inning, the Padres loaded the bases with one out, but Everth Cabrera struck out looking and Nick Hundley flied out to center field. The Padres finally busted out in the ninth.
Vincent and Amarista were the center of the clubhouse celebration.
"I'll never forget it right there," Vincent said. "That was pretty awesome."