HOUSTON (AP) -- Listed at 5-foot-7 and 150 pounds, Alexi Amarista is one of the smallest players in the majors.
His ninth-inning grand slam couldn't have been bigger for the San Diego Padres on Thursday night.
Amarista's first major league home run capped a six-run rally in the ninth inning off Houston closer Brett Myers and lifted the Padres to a 7-3 win over the Astros.
The victory ended a streak of 119 straight losses by the Padres when they trailed after eight innings.
Amarista laughed when asked if people should be surprised that he can hit a home run.
''I play hard and I don't know what they think,'' he said through a translator. ''I just like to play ball hard.''
Andrew Cashner held Houston hitless for six innings in only his third big league start. Carlos Lee broke up the bid with a one-out single in the seventh and Brian Bogusevic followed with a homer for a 2-1 lead.
The Astros added a run in the eighth, and Myers (0-3) came on in the ninth with a 3-1 lead.
Myers allowed a leadoff double by pinch hitter John Baker and a one-out single by pinch-hitter Mark Kotsay. Third baseman Chris Johnson's second error of the game gave San Diego a run, and Carlos Quentin was hit by a pitch with the bases loaded, tying it at 3.
With two outs, Amarista homered into the second row in right field. The shot by Amarista, who looks smaller than his listed height, sent the few remaining fans streaming for the exits.
''Even though he's slight of stature, he takes a rip,'' Padres manager Bud Black said. ''He got a pitch sort of middle in and he turned on it. He's always ready to hit. His intent is to hit. His intent isn't to take pitches.''
The 23-year-old Amarista was brought up from Triple-A on May 17 after being acquired in a trade with the Los Angeles Angels earlier that month.
He received a beer shower from his teammates to mark his big night.
''It was emotional,'' he said. ''The first home run was a big emotion and I'll never forget it.''
Myers wished he could take the entire inning back.
''I gave up runs. That's not my job. I'm supposed to shut down the inning and I didn't do it,'' he said.
Only one of the six runs Myers allowed was earned, but he said that didn't matter.
''I don't blame it on anything except me,'' he said. ''It's my job to shut the inning down and pitch around mistakes. If I can't do that, that's my fault.''
The Astros couldn't do anything against Cashner through the first six innings as he kept them off-balance relying on a fastball clocked as high as 99 mph mixed with sliders and curves.
''He can take this outing and come away with a lot of confidence how he threw the ball moving forward,'' Black said.
Cashner retired Jed Lowrie to start the seventh inning before Lee's hit to shallow single to center field assured that the Padres would remain the only franchise in major league baseball without a no-hitter.
Bogusevic's soaring shot that pinged off the second deck in right field chased the 25-year-old Cashner. He crouched down as he watched the ball sail away, before getting up and shaking his head.
Cashner said he didn't spend much time worrying about the possibility of a no-hitter.
''I never really try to think about that stuff,'' he said. ''I just try to make pitches. 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.''
J.D. Martinez walked in the Houston eighth, reached third on a single by Scott Moore and scored on a wild pitch by Nick Vincent (1-0).
Dallas Keuchel, who was also making the third start of his career, yielded four hits and four walks with a run in six innings. Keuchel pitched a complete game for his first major league win in his last start for Houston.
Cashner made 27 relief appearances for the Padres this season before going 2 1-3 innings in a start on June 9. He was sent to Double-A San Antonio after that to work on his transition from reliever to starter. He went 2-0 with a 1.88 in three starts there.
The Padres moved Cashner out of the bullpen in an attempt to bolster a rotation decimated by injuries that has used 13 different starters this season.
Cashner retired the first five batters he faced before walking Jason Castro with two outs in the second inning. He immediately got back on track retiring the next 14 batters, with eight strikeouts including the side in both the third and sixth innings.
He finished with nine strikeouts and a walk in 6 1-3 innings.
Cashner, who went to school in Conroe, which is just outside of Houston, had his own cheering section of friends and family who held up signs spelling out each letter of his last name.
NOTES: Houston 2B Jose Altuve was out of the lineup for the fourth straight game with a strained right hamstring. Manager Brad Mills doesn't expect him to play until at least Sunday. ... San Diego optioned RHP Brad Brach to Triple-A Tucson before the game to make room on the roster for Cashner. ... San Diego's Ross Ohlendorf will move from the rotation into the bullpen as a long reliever, making Kip Wells the starter on Sunday against the Rockies. ... Houston optioned LHP Xavier Cedeno to Triple-A Oklahoma City after the game to make room for Bud Norris, who will be activated from the DL to start Friday's game at Chicago. ... Houston OF Travis Buck accepted his minor league assignment and was outrighted to Triple-A Oklahoma City.