Having already clinched their first winning series in almost two months, the visiting Astros look to record their first-ever sweep of the struggling A's on Thursday.Since the teams first met during interleague play in 2002, Houston (39-80) dropped 16 of 18 against the A's and went 0-6 in Oakland before pulling out the first two of this set. One night after holding on for a 5-4 win, the Astros won 2-1 in 11 innings to record their first winning series since taking two of three against Milwaukee from June 18-20."We're sticking together," said backup catcher Carlos Corporan, who delivered the go-ahead double to send the Astros to consecutive wins for the first time since a four-game run June 12-16."We're having a really good time right now."Oakland (67-52), meanwhile, has lost nine of 13. The A's, who held a six-game lead over Texas in the West on July 29, trail the surging Rangers by two.They went 0 for 9 with runners in scoring position Wednesday and had a potential game-winning homer in the 10th taken away when Robbie Grossman made a leaping grab of Chris Young's deep fly at the fence. Young barely missed homering in the ninth Tuesday on a foul ball that was reviewed."It just seemed like it was frustrating from the beginning and got more frustrating as the game went on," said manager Bob Melvin, who was ejected in the eighth for arguing a call at third base.Last swept at home by the Los Angeles Angels from Sept. 3-5, the A's hope to continue their recent success against scheduled Astros starter Erik Bedard (3-8, 4.28 ERA).The left-hander has allowed eight runs and walked nine over 5 1/3 innings while going 0-1 in two starts against the A's this season. He gave up six of those runs in one-third of an inning during an 11-2 loss at Oakland on April 15.Bedard is 0-5 with a 3.98 ERA in his last seven starts, but the Astros have been shut out three times and lost each during the stretch. He gave up three runs in 6 2/3 innings but did not factor in the decision of a 9-5 loss to Texas on Friday.A bullpen that ranks last in the majors with a 5.32 ERA has blown one-run leads in each of Bedard's last two starts.Philip Humber allowed the tying run in the seventh Wednesday after rookie Jarred Cosart threw six strong innings, but the next three Houston relievers yielded one hit and no walks over 3 2/3 innings.Houston All-Star catcher and Bay Area native Jason Castro is batting .370 with 10 RBIs during a hitting streak that reached 12 games with a single Wednesday.Brandon Moss drove in Oakland's lone run, but he is 5 for 27 in his last eight contests.Making his home debut in the finale, Sonny Gray (0-1, 1.80) allowed four runs -- two earned -- with four hits and three walks in six innings of a 5-4 loss at Toronto on Saturday in his first career start."The longer the game went, the more comfortable I started becoming," said the right-hander, who opened his career with two scoreless relief appearances last month.