Aug. 28, 2011BOX SCORE GIANTS VIDEOMLB PAGE MLB SCOREBOARDSAN FRANCISCO (AP) -- Matt Downs delivered a go-ahead single with one out in the 11th inning and the Houston Astros beat the stumbling San Francisco Giants 4-3 on Sunday to salvage a four-game split.Jose Altuve got things going with a one-out double against Ramon Ramirez (2-3) and Downs followed with a single up the middle. Altuve was forced into action after slugger Carlos Lee left in the top of the ninth with a sprained right ankle sustained sliding into second on a double.Mark Melancon (7-4) pitched the 10th and got the win despite allowing Mark DeRosa's tying single. David Carpenter finished for his first career save.The reigning World Series champions fell four games behind the first-place Diamondbacks in the NL West race after Arizona beat the Padres 6-1.On bring your dog day at AT&T Park, the Giants continued to experience the dog days. More missed chances.They also argued that one chance was taken from them.DeRosa singled with one out in the 10th off Melancon, but was thrown out trying to stretch it to a double. He slid past the bag and reached back with his left hand, and replays showed he appeared to be safe.DeRosa jumped up to yell at second-base umpire Dan Bellino and manager Bruce Bochy was ejected for the second time this year.Houston went ahead 3-2 in the 10th on pinch-hitter Jason Michaels' double, then the Giants came back again.Jordan Schafer lined a tying single to right with two outs in the eighth against Matt Cain to help force extra innings.The reeling Giants failed to string together their first three-game winning streak since July 17-19 at San Diego. They haven't had a winning home series in five sets since taking two of three from Milwaukee from July 22-24.San Francisco has played eight straight games decided by two or fewer runs.The Giants couldn't capitalize in the eighth after getting consecutive two-out singles by Jeff Keppinger and Carlos Beltran off Wilton Lopez. Wesley Wright relieved and retired Pablo Sandoval on a grounder.Aubrey Huff hit a tying RBI single off Houston starter Bud Norris in the seventh to end a 0-for-15 funk, and singled again in the ninth but the Giants didn't score. After Huff's initial hit in the seventh, Norris received a mound visit before giving up Orlando Cabrera's go-ahead sacrifice fly on the next pitch.That one-run lead didn't last long.Lee doubled against Sergio Romo in the ninth and hustled to beat the throw from right field. He came in hard to collide with shortstop Cabrera. Lee's right leg bent and it appeared the spikes on his right shoe got caught on the bag. He grabbed his right ankle in pain as the training staff rushed out to help him off the field.Lee went 3 for 4 with two doubles.Norris had only allowed one runner to reach second base before the Giants got to him for two runs in the seventh. Sandoval, whose two-out single in the fourth was the first hit allowed by Norris, drew a one-out walk to start things off. Brandon Belt singled to bring up Huff, whose struggles have some fans and skeptics calling for Bochy to sit him for an extended period.Cain, the Giants' hard-luck loser for years now, has only two wins in his last nine starts. The two-time All-Star struck out pinch-hitter Jason Bourgeois with the go-ahead run on first for the second out of the eighth, then gave up Schafer's tying single.Cain has received the lowest run support in the majors since his first full season in 2006.NOTES: Astros SS Clint Barmes had the day off. ... RHP Tim Lincecum takes the mound Monday for the Giants against the Chicago Cubs. The two-time NL Cy Young Award winner is 3-1 with a 0.91 ERA in his last four starts. ... Houston heads home to face Pittsburgh, with Wandy Rodriguez (9-9) getting the ball for the fourth time this year against the Pirates. He struck out 11 Pittsburgh batters in 5 2-3 innings back on July 17. ... Astros C Jason Castro, sidelined all season after right knee surgery, will join the team in Houston for the homestand to catch bullpens and take batting practice before returning to Florida for instructional league. "It will be a good chance for us to see him and evaluate where he is," manager Brad Mills said. ... Mills left passes for his old community college coach at College of the Sequoias, Bert Holt, and his wife, Sue.